MEASUREMENTS
A measurement is a comparison. We measure the length of a lot by comparing it with the standard of length, the yard or foot. We measure a farm by comparing its area with the standard unit of surface measure, the acre, square rod, or square yard.
In every measurement we must first have an accepted standard unit. The history of units of measurement is a very interesting one, and its difficulty arises from the fact that no two things in nature are the same. One of the ancient units of length was the cubit, supposed to be the length of a man's forearm, from the elbow to the end of the middle finger. This, like other natural units, varied and was therefore unreliable. As civilization progressed it became necessary for the various governments to take up the question of units of measurements and to define just what they should be.
Our own standards are copied from those of Great Britain, and although congress is empowered to prescribe what shall be our units, little has been changed, so that with few exceptions we are still using English measurements.
The almost hopeless confusion and unnecessary complication of figures is shown in the following tables as compared with the metric system:
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The original English definition of an inch was "three barley corns" with rounded ends. The meter is 1/10,000,000 (one ten-millionth) of a quadrant of the earth's circumference, i. e., the distance from the pole to the equator measured along one of the meridians of longitude. The length of three barley corns might be different from the next three, so here was the original difficulty again. The designers of the metric system went back to the earth itself as the only unchangeable thing—and—are we sure there is no change in the earth's circumference? The great advantage of the metric is that it is a decimal system and includes weights as well as surfaces and solids. Our weights are even more distracting than our long measure. We have in fact two kinds of weight measure—troy and avoirdupois.
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In surface measurements, the same differences are seen:
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In measures of volumes we are as badly off:
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As if this were not enough, when we go to sea we use another system. The depth of water is measured in fathoms (6 feet = 1 fathom), the mile is 6086.07 feet long = 1.152664 land miles, and 3 sea miles = 1 league. In our cubic measure:
| 1728 cubic inches | = 1 cubic foot |
| 27 cubic feet | = 1 cubic yard |
| A cord of wood is 4 ft. × 4 ft. × 8 ft. | = 128 cubic feet. |
| A perch of masonry is 161⁄2 × 11⁄2 × 1 | = 24.75 cubic feet |
Isn't it about time we used the metric system? The reader will not mind one more standard unit. Lumber is measured by the board foot. Its dimensions are 12 × 12 × 1 inches; it contains 144 cubic inches and is 11⁄12 of a cubic foot. A board 10 feet long, 1 foot wide and 1 inch thick contains 10 board feet. One of the same length and width but only 1⁄2 inch thick contains 5 board feet.
The contents of any piece of timber reduced to cubic inches can be found in board feet by dividing by 144, or from cubic feet by multiplying by 12. As simple examples: How many board feet in a piece of lumber containing 2,880 cubic inches? 2880⁄144 = 20 board feet. How much wood in a joist 16 feet long, 12 inches wide and 6 inches thick? 16 × 1 × 1⁄2 = 8 cubic feet: 8 × 12 = 96 board feet. A simpler method may be used in most cases. How much wood in a beam 9 inches × 6 inches, 14 feet long? Imagine this timber built up of 1-inch boards. As there are nine of them, and each 14 ft. × 1⁄2 foot × 1 inch and contains 7 board feet ([Fig. 235]), 7 × 9 = 63 board feet. Again, how much wood in a timber 8 inches × 4 inches, 18 feet long? This is equivalent to 4 boards 1 inch thick and 8 inches or 2⁄3 foot wide. Each board is 18 × 2⁄3 × 1 = 12 board feet, and 12 × 4 = 48, answer. (See b, [Fig. 235]).
To take a theoretical case: How much wood in a solid circular log of uniform diameter, 16 inches in diameter, 13 feet and 9 inches long? Find the area of a 16-inch circle in square inches, multiply by length in inches and divide by 144.
| 16 × 16 × .7854 = 201 | 13 ft. 9 in. = 165 inches |
| (201 × 165)⁄144 = 13045⁄144 board feet | |
It is not likely that a boy would often need to figure such an example, but if the approximate weight of such a timber were desired, this method could be used, reducing the answer to cubic feet and multiplying by the weight per cubic foot.
A knowledge of square root is often of great value to the woodworker for estimating diagonals or squaring foundations. The latter is usually based on the known relation of an hypothenuse to its base and altitude. It is the carpenters' 3-4-5 rule. The square of the base added to the square of the altitude = square of the hypothenuse. 3² = 9, 4² = 16; 9 + 16 = 25. The square root of 25 is 5. (See [Fig. 235]). To square the corner of his foundation the carpenter measures 6 feet one way and 8 the other. If his 10-foot pole just touches the two marks, the corner is square. 6² = 36, 8² = 64; 36 + 64 = 100. √100 = 10. This method was used in laying out the tennis court, the figures being 36, 48, 60—3, 4, and 5 multiplied by 12.
To take a more practical case, suppose we are called upon to estimate exactly, without any allowance for waste, the amount of lumber in a packing case built of one-inch stock, whose outside dimensions are 4 feet 8 inches × 3 feet 2 inches × 2 feet 8 inches. Referring to the drawing ([Fig. 235], d), we draw up the following bill of material:
| 2 | pieces | (top and bottom) | 4 ft. 8 in. × 3 ft. 2 in. |
| 2 | ″ | (sides) | 4 ft. 8 in. × 2 ft. 6 in. |
| 2 | ″ | (ends) | 3 ft. 0 in. × 2 ft. 6 in. |
The top and bottom, extending full length and width, are the full dimensions of the box, while the sides, although full length, are not the full height, on account of the thickness of the top and bottom pieces—hence the dimensions, 2 feet 6 inches. From the ends must be deducted two inches from each dimension, for the same reason. In multiplying, simplify as much as possible. There are four pieces 2 feet 6 inches wide; as their combined length is 15 feet 4 inches, we have 151⁄3 feet × 21⁄2 feet = 381⁄3 square feet. The combined length of top and bottom is 9 feet 4 inches = 91⁄3 × 31⁄6 = 295⁄5 , and 381⁄3 + 295⁄5 = 678⁄5 or 68 board feet, ignoring such a small amount as 1⁄5 of a foot. This is close figuring, too close for practical work, but it is better to figure the exact amount, and then make allowances for waste, than to depend on loose methods of figuring, such as dropping fractions, to take care of the waste.
Fig. 235. A packing case
As a good example of estimation, take the hexagonal tabourette shown in [Fig. 178]; the five pieces, aside from the hexagon under and supporting the top, which may be made from scrap lumber, are shown laid out in [Fig. 236]. The board must be at least twelve inches wide in order to get out of it the large hexagon. The legs may be laid out as shown with space left between for sawing, yet even by this method considerable waste will result, and it should be kept constantly in mind that as far as possible waste is to be reduced to a minimum. "Wood butcher" is the common shop name for the workman who spoils more material than he uses.
The great advantage of making out a bill of material before starting is that it not only makes you study your drawing, but causes you to consider the best method of laying out the blank pieces.
Fig. 236. Laying out the pieces for a tabourette
It is often necessary to find the areas of figures other than the square or parallelogram. Assume that we are to floor a room in an octagonal tower or summer house. If the distance across the flat sides of the octagon is sixteen feet, leaving out the item of waste, how many square feet will be required?
Fig. 237. Finding the area of an octagon
The octagon may be drawn in a square and its area will be that of the square, less the four triangles in the corners. ([Fig. 237]). So the problem resolves itself into finding the area of one of these triangles. If we knew the length of one of the sides of the octagon, the solution would be simple, but we only know that the eight sides are equal. The following method may be worked out: Find the diagonal of the sixteen foot square. It is 22.6+. Deduct the distance across the flats, 16, leaving 6.6 feet equally divided between a and b; a = 3.3 and it may be proved that c = a = d. So in each corner we have a triangle whose base is 6.6 × 3.3. The area of a triangle equals half its base by the altitude. Therefore the area of each triangle is 3.3 × 3.3 and 3.3 × 3.3 × 4 equals 43.56 square feet, the combined area of the four corners. This deducted from the area of the square leaves the area of the octagon, or 256-43.56 = 212.44 square feet.
Fig. 238. Problem of the hexagon
Assume that our problem is to find the narrowest board we can use to cut out a hexagon whose diameter is fourteen inches. As shown in Chapter IV, the hexagon is drawn in a circle. One of the sides is equal to the radius or half the diameter. This gives us the arrangement shown in [Fig. 238], in which our problem is confined to the right-angled triangle whose base is seven and hypothenuse fourteen. From our knowledge of triangles, we deduct the square of seven (49) from the square of 14 (196), leaving 196-49 = 147, which is the square of the altitude. Then √147 = 12.12, which is the narrowest board from which we can obtain a hexagon 14 inches in diameter.
These examples are given to show the close connection between woodwork and arithmetic.
[LII]
LUMBER: NO. 1
It is hardly possible for a boy to select and purchase wood for his various purposes without some knowledge of the different woods and their peculiar characteristics. No two are exactly alike, and in fact two trees of the same kind growing in different parts of the country under different conditions will produce timber of very different qualities. This is specially noticeable in the tulip or white wood, for example. A tree of this species, growing in a swamp in the South, will yield a very different wood from one grown on high ground in the North.
Again, the same wood is known in different localities by different names, so in order to have a sound knowledge of lumber, it is really necessary to know something about the trees. White wood, just mentioned, is called, in many localities, yellow poplar. As a matter of fact, it is not a poplar, nor is it related to the poplars, being a member of the magnolia family.
The following pages, devoted to this subject, are the cream of many talks between our boys, boiled down to the important facts and arranged in some order. It was a hobby of Ralph's, and Harry became so enthusiastic over it that they frequently laid aside their work and took long walks through the country studying trees.
Harry started a small nursery in the garden and is raising young trees from seeds and cuttings. As he remarked to Ralph one day: "It's astonishing how little people know about trees! Why they are the most interesting things that grow. Just think how many things we get from them besides wood; maple sugar, rubber, turpentine, wood alcohol, tannin for making leather, shellac, Canada balsam, spruce gum, and nuts! All of our nuts except peanuts come from trees—hickory, walnuts, butternuts, beechnuts, chestnuts, pecans, almonds, etc."
Ralph noticed that as Harry's interest in the trees grew he became less wasteful of his wood in the shop. The fact that a tree had to be cut, and in most cases killed, in order to furnish him with lumber, seemed to worry him. One day when he was thoughtfully at work in the shop, he blurted out, "It's a shame that so many trees have to be cut down for lumber!"
"Yes," said Ralph, "it seems so; yet if no lumber was wasted, it would not be so bad. It is estimated that 75 per cent. of the wood cut down is wasted."
"How?" asked the boy.
"Well, in the first place, many lumbermen after cutting the tree down, take just the log or lower part and leave the top to decay. It often happens that they leave the tops and branches as a great mass of litter, which soon becomes as dry as tinder, an invitation to the smallest spark to start a fire, and more woodland is destroyed by fire each year than I care to tell you."
"How much?" asked Harry.
"Every year, between twelve and fifteen million acres, and some years three times as much."
"How much is a million acres?"
"You can get some idea from this: Long Island, N. Y., is a hundred miles long and about twenty across in the widest part. It contains about a million acres. Imagine this covered by solid woods, multiply by fifteen and you would have a good idea of the amount of woodland burned over every year."
"Gracious!" exclaimed the boy. "I should think every tree would have been burned years ago."
"Well, this is a big country," said Ralph. "I figured it out once. The United States is large enough to make six hundred states the size of Connecticut, and have room for twenty-five or thirty more. The state of Texas alone could be cut up into a hundred pieces as large as Connecticut.
"The forest fire is one of our worst enemies. It is far worse than the lumberman, because when he cuts down trees it gives hundreds of young seedlings which are struggling to live in the shade a chance to grow and cover the ground with a new forest; but the fire kills these young seedlings and even burns the seeds that are lying in the leaves waiting to grow. That is one of the worst things to be said against the forest fire."
"Does it kill every tree?"
"Oh, no! Trees like the oak sprout from the old roots, but most evergreen trees are killed outright."
"What happens then?"
"Why, it depends. If the forest is mixed, hard woods and conifers, the hard woods, or some of them, will in time send up sprouts, and where you formerly had a mixed stand, you will in a few years have only hard woods, unless some of the evergreens were not touched. In that case, their seeds will in time replace the old evergreens."
"From forty to a hundred years to have a large forest. Some evergreens, like the spruce, increase in diameter very slowly."
"What happens when the forest that is burned is all evergreens, and they are all killed?" asked the irrepressible boy.
"The process of reforesting in that case is very slow. Trees of little value, like the poplar or birch, appear first, because their seeds are light and are carried a considerable distance by the wind. If fires pass over the same area every few years, the forest will never come back unless seeds are planted. There are large areas in this country thus denuded, and instead of a forest we have a scrubby growth of bushes that are of little value to anybody.
"Huckleberries grow in burned-over land luxuriantly, and in some sections it is suspected that the people who make money by gathering the berries burn the brush purposely.
"The forest cover is valuable for other things besides timber. The snow melts slowly in an evergreen forest, because the rays of the sun cannot penetrate with full strength. This allows the water to sink into the ground slowly, and to come out lower down in the form of springs.
"Where there is no forest the snow melts much more quickly, the water rushes down the hills in streams, carrying with it the top soil, which is of so much value to the farmer, cutting the hillsides into gullies, causing floods in the valleys, and filling up the rivers with silt or mud.
"This spoils the streams, ruins the land, and causes millions of dollars' worth of damage to property. If you doubt it, read the newspaper accounts of floods in the valleys of the Ohio, Missouri, and Mississippi every spring."
"But I should think by this time all the soil would be washed away."
"It will be in time. There are large areas in China where the soil is washed away to the bare rock. The population has been obliged to emigrate because when the soil goes, the population can no longer live."
"Well, what are we going to do about it?" asked Harry in amazement.
"Wait a minute," said Ralph, warming up to his subject. "The Mississippi carries into the Gulf of Mexico every year seven and a half billion cubic feet of soil; enough to cover Long Island two inches deep every year."
"What are we going to do?" repeated the boy.
"We can do one of two things," said Ralph sagely, "We can follow in the footsteps of China and let the land go to ruin; or we can follow the example of Germany, take care of our forests—or what is left of them—and plant new ones. It is one of the greatest questions in this country to-day, and you are going to hear a lot about it before you are twenty-one."
[LIII]
LUMBER: NO. 2
The lumber business ranks fourth in the great industries of the United States. The Department of Forestry at Washington estimates that we are using three times as much wood yearly as the annual growth of the forest.
A grand total of 150,000,000,000 board feet of lumber for all purposes, including firewood, is the estimated amount, a figure the mind can hardly grasp.
The railroads of our country rest on 1,200,000,000 ties. The average life of a tie is about ten years, so that we must replace one tenth, or 120,000,000, each year. As the average forest produces two hundred ties to the acre, this item alone calls for half a million acres of woods every year.
The tie is only one item in the great business of railroading, immense quantities of lumber being required for trestles, platforms, stations, bridges, etc., so that a full million of acres must be cut annually to keep our railroads operating.
Place this item against the fifteen million burned, and the statement may be made that we burn enough each year to supply the railroads for fifteen years. To offset this loss several railroad companies are now planting trees for a future supply, as the many attempts to supplant the wooden tie with a manufactured one have not been very successful.
The six thousand mines of various kinds within our border use up 5,000,000,000 board feet every year, and so on through the list of wood-consuming industries. As our population doubles, the consumption of lumber quadruples. To-day, five hundred feet of wood is used annually for every man, woman, and child, as compared with the sixty feet used in Europe. Already our many industries are beginning to feel the shortage, and prices constantly go up.
Turpentine, which is made from the Southern yellow pine, requires a new "orchard" of 800,000 acres yearly to keep up the demand; and when we realize that one third of the lumber cut is yellow pine, it is little wonder that the price of turpentine and other naval stores keeps moving upward.
Where and when will it stop? We read a great deal about the transformation of water power into electrical energy, but the flow of streams is dependent on forests, and the spring floods are followed by drought. While the Ohio River rises forty feet in the spring, it is possible to walk over the river bed almost dry shod the following summer.
We hear much about irrigation, but irrigation is dependent largely on mountain forests.
So a burning question has arisen in these United States, called conservation, or the husbanding of the great resources that have made our country what it is.
The forest resources are different from those of the mines. There is a definite end to the supply of coal, iron, gold, and silver, but by proper care the forest may be made to yield a continuous crop of lumber.
Forestry does not mean the fencing in of the woods, but the handling of them in such a way that no more is cut than the annual growth. This has been practised in Germany on scientific principles with such success that the production has been increased 300 per cent., and where seventy-five years ago they obtained twenty cubic feet from each acre a year, they now cut sixty, and the forest continues to grow luxuriantly.
What Germany has done we can do, and millions of acres now useless can be made to yield large quantities of wood while continually clothed with growing forests.
The cutting of lumber is usually done when the sap is dormant, preferably in the winter. The logs are gotten to the mill by the cheapest method, which usually consists in floating them down a stream or river; but now that most of the remaining forest is remote, it is quite common to have portable mills transported into the woods where the trees are cut and sawed into planks or the larger sizes of timber and from there loaded on the cars.
The old-fashioned method was more picturesque, and the "drive" started with the breaking up of the ice in the spring. Thousands and hundreds of thousands of logs were guided down stream, pulled off shore when they became stranded, and the jams were broken up until the smooth water below made sorting possible.
As several companies might be driving down the same stream, each log was marked by an axe with the private mark of the one to which it belonged. After many vicissitudes, the drive would reach the sorting boom, where the lumber of the various companies would be separated and made up into rafts.
A boom is a chain of logs fastened together by iron chains, and extending into the river. It may reach clear across, or one end can be anchored in the stream to allow a passage for boats. In that case the river end has to be anchored up stream to catch the logs.
One of the most serious things encountered on a drive is the log jam. It may be caused in many ways but usually by some obstruction, as a shoal, rocks, a narrowing of the river, etc.
The lumberman has a vocabulary of his own, and he recognizes several kinds of jams, such as wing jams, solid jams, etc.
No matter how caused, it is the business of the lumber jack to break up the jam, and sometimes before it can be done a late freeze will occur and the whole mass become solid ice and logs. It is sometimes necessary to use dynamite to break it up. The breaking up is a dangerous time for the driver, who must sometimes run for his life across the moving mass of logs to the shore.
After they are made into rafts, steamers are used to tow the logs to the various mills. It is slow work, but when the destination is reached, the real process of converting the tree into lumber begins. Often the rafts stay in the water for months before being broken up, and the logs guided to the endless chain which drags them up into the mill.
From this time on the action is very rapid. The modern mill is a mass of rapidly moving machinery, guided and controlled by comparatively few men. Three distinct classes of saws are used—circular, band, and gang saws, and different mills in the same neighborhood use different methods.
Band saws are continuous bands of steel, often 48 feet long, and as wide as 8 inches, which pass over two large wheels like a belt. Gang saws are straight and move up and down rapidly. A number of them are fastened to horizontal pieces, the distance apart being adjustable to the thickness of timber desired.
Before passing through the gang saw, the logs are usually edged, i. e., a slab is cut from two opposite sides. The log is then turned over on one of these flat sides, so that as it passes through the gang saw the planks are all the same width.
The slabs or edgings are passed through other saws and cut to the width and length of a lath, all the waste possible being made into lath or other by-products.
As we use four billions of lath a year, this is an important item.
The process varies with the kind of lumber and its future purpose, but a great deal is wasted in many mills. The refuse is used for fuel, and in some cases burned in stacks built specially for the purpose of getting rid of it. This is one of the forms of waste which will undoubtedly be done away with in the future, and already many lumbermen are at work on the problem. The sawdust is conveyed directly to the furnaces under the boiler and used in the generation of steam.
[LIV]
LUMBER: NO. 3
Having finally reached the commercial stage, the lumber is shipped away from the mill either by water or by rail to the lumber yards of the country.
Here it should be seasoned. In the past this process consisted of piling the planks in the open air in such a way that air could circulate freely through the pile, allowing the sap to evaporate and the wood to dry evenly. This was a sure but slow process, and in the hurry of modern life quicker methods have been tried.
One of these is known as kiln drying, by which the time is reduced to a few weeks. It consists of piling the wood in a room like a kiln and drying it by artificial heat. The result is not so satisfactory as the natural method, because the sap near the surface hardens and prevents the inner moisture from escaping, so that kiln-dried lumber while dry at the surface is "green" inside. When planed till part of the surface is removed the green wood is brought near to the air again, and warping is liable to occur.
Other methods have been tried, such as steaming to vaporize the sap, and soaking in hot water for the same purpose. Of course these processes all add to the cost of lumber, yet so valuable is time that it is difficult to obtain good old-fashioned seasoned wood unless it has lain for some time in a local yard.
In order to understand the phenomena of warping, shrinkage, checking, shakes, etc., it is necessary to know something of how the tree grows. Like all living organisms, it is made up of minute cells. The new cells are formed on the outside of the tree under the bark, and here the sap is most active. The cause of the flow of sap is not very clearly understood, but it corresponds to blood in the human body, in that it carries the nourishment that forms the cells. As a new mass or layer of soft new cells forms each season, the layers may be distinctly seen and counted, but the line of separation is not a sharply drawn one, as we find by examining a cross section of wood with the microscope. However, the layers or annual rings are distinct enough to be counted, so that the age of the tree at the time it was cut down may be readily discovered.
The new or sap wood, then, is further from the centre each year, and while the old cells may not be dead, they contain less and less sap, are therefore drier, and after a few years change colour, becoming darker.
There is often a very great contrast between the colour of the heart wood and that of the sap wood, although the latter may be represented by several years of growth.
These annual rings are not actually circular, but very irregular, and often wider in some parts than in others. The study of these rings is very interesting, and it shows that the tree usually increases in diameter more rapidly during the first few years than later. Very often, after growing slowly for several years, the tree will apparently grow rapidly again. The cause of this cannot be determined without a knowledge of the tree's history.
It has been proved by experiment that thinning the forest increases the growth of the remaining trees 18 per cent., and these peculiarities in the rings may have been due to some like cause. The bearing of this fact on the peculiarities of warping and shrinkage is that when cut down the log is drier at the heart and more sappy at the outside, so that evaporation occurs near the surface.
Fig. 239. Warping, wind, and shrinkage.
The effect of it is shown in [Fig. 239]. The outside drawing together has opened the wood, or "checked" it, most at the outside, diminishing toward the centre. The evaporation would have occurred just the same had the log been cut into planks, causing them to curl as shown at a. This is known as warping, and it is one of the troubles of the woodworker. In construction it must be constantly guarded against, and overcome as far as possible. It cannot be entirely prevented, but if the wood has been well seasoned before it is used a large part of the warp will be taken out in the planing mill, or in the squaring up.
Twisting, winding, and warping are also caused by the two sides of a board having been subjected to different degrees of heat, moisture, etc. If a plank is laid on the floor, the upper part is more exposed to the air and to changes of temperature and humidity; therefore it curls.
If a board is stood on end or placed in a rack where there is a free circulation of air, the curling will be much less. Even in a rack, if several boards are piled one on another, the top one will have different conditions from the others and be apt to curl or wind.
Shrinkage is a term applied to the decrease in diameter of the tree, due to sap evaporation.
Fig. 240. Effect of shrinkage on lumber
In the case of the board it means a decrease in width, and it varies greatly in different trees and their woods. As shrinkage is always across the grain, its effect on a common joint may be illustrated in [Fig. 240]. At a is shown a middle lap joint just put together. If the wood is not well seasoned, shrinkage will in time change it to the form shown at b, which is exaggerated to make the meaning clear.
A square piece of timber, one corner of which is the centre of the tree, will change from c to d. Shrinkage as well as warping must be taken into consideration in construction.
Fig. 241. The development of the panelled door
The development of the panelled door is a good illustration. Suppose we wish to close a space with a door, knowing little about shrinkage. Let us construct it by the simplest method, say four vertical boards. If the width of these boards equals the opening when the door is built ([Fig. 241]) there will soon be an opening wide enough for the fingers to enter and lift up a latch on the inside. The door is very much of a failure. We notice, however, that there is no opening at top or bottom. An idea! We construct a door with planks placed horizontally. Now although we find after a while no opening at the sides we do find openings at top and bottom. The panelled door is not constructed solely for beauty but to overcome shrinkage as far as possible. [Fig. 241] shows the various parts. The rails maintain the width, the only shrinkage being in the cross grain of the stiles, and they preserve the height except for the small amount in the rails. The remaining spaces are panelled, the construction being shown at a. Both stiles and rails have a groove plowed out to receive the edges of the panel. This should be free to shrink in the grooves, where it is invisible, but if the mistake is made of fastening the panel edges rigidly in these grooves the panel will shrink anyway and frequently split from top to bottom.
Many other forms of construction which we have seen daily as long as we can remember have equally sound reasons for their form. No piece of woodwork should be designed without considering how it will be affected by shrinkage and warping.
In selecting lumber always look out for "shakes." This is a defect caused by the separation of the annual rings. A tree may be considered as a series of irregular cylinders of diminishing diameters. The forest-grown tree is much more spindling, tall, and straight than the low-crowned, heavy-branched specimen grown in the open, where there is no crowding.
The swaying of the forest tree in the wind, especially when its neighbours have been cut down, is sometimes sufficient to make the rings separate and slide one within the other. This is more noticeable in some species than others and it gives the wood a serious fault. ([Fig. 239]).
"Winding" is the result when the ends and sides are no longer parallel. Like all peculiar characteristics of wood, this varies greatly in lumber of various kinds, and may be largely avoided by exposing both sides to the same conditions, or keeping equally distributed weight on it until used. When winding becomes excessive, the board is useless for any kind of work.
[LV]
LUMBER: NO. 4
The woods of the United States are classified roughly as hard and soft; and trees as broad-leaved or deciduous, and evergreen or coniferous.
In a general way, the trees which drop their leaves in the fall—the broad-leaved—produce hard woods and the evergreens soft woods. There are so many exceptions, however, that the rule is a very rough guide.
Several of the coniferous trees drop their leaves or needles in the fall, like the larch or tamarack, and some woods from evergreens are harder than some woods from broad-leaved trees. Yellow pine is harder than basswood, which, according to the rule, should be a hard wood. As a matter of fact, it is softer than the majority of woods cut from evergreens. The only way to gain a comprehensive knowledge of this interesting subject is by experience and study. Making a collection of woods, leaves, and seeds is one of the most fascinating studies a boy can take up. He will soon discover that not only is every wood different from every other wood in grain, colour, odour, and hardness, but some woods are strong and elastic, others strong and brittle, weak, etc., and that every tree has a different leaf, bark, flower, and seed from its neighbour. He will find groups or families, such as the oaks, the maples, the pines, spruces, cedars, etc., with several members of each group, all different, yet having family characteristics. He will be surprised at the endless extent of the subject; the willow for instance has a hundred and fifty known varieties. He will find himself, like our boys, dipping into botany and geology to discover perhaps, as Harry did, that the oak was once an evergreen, and that it still holds a good proportion of its leaves all winter.
He will learn that there are broad-leaved evergreens like the laurel and rhododendron; that some trees are evergreen in the South, and lose their leaves in the North; that some shrubs of the Northern states become trees farther south. He may even wrestle with the problem "What is a tree?" or, "Where does the shrub leave off and the tree begin?"
The study of the many methods nature has devised for distributing seeds has evolved whole volumes; so has the question of how the buds on the trees are protected in winter. There are definite ways in which the tiny leaves are folded up in these winter buds, all ready to unfold in a certain way in the spring. Perhaps the reader wonders what all this has to do with woodwork, but to a boy who once begins to collect specimens, it will follow as a matter of course. Knowing something about woods he naturally begins to study trees, and gradually observes the wonderful phenomena of growth, flower, and seed. Planting seeds to see how they grow is the next step, and before long he has a young nursery in the yard; while the reading of the work of such men as Luther Burbank will induce him to try his hand at grafting and budding.
The man who makes two apples grow where one grew before is as valuable a citizen as the man who makes two blades of grass grow in the place of one. When Mr. Burbank converts the prickly cactus into a thornless cactus, valuable as a forage plant, he is conferring a great benefit on the whole race by making millions of acres of desert land available for stock raising.
Incidentally, these wonders performed by the Wizard of California will not die with Mr. Burbank, but will constitute the beginning of a new profession which, combined with forestry, will offer a tempting field for the rising generation.
COMMON TIMBER TREES AND THEIR WOOD
EVERGREENS OR CONIFEROUS TREES
White Pine.—One of our most beautiful evergreens. Growing throughout the North-eastern and Lake states, and formerly forming dense forests from the Bay of Fundy to Minnesota. Needles grow in groups of five of a light bluish green from three to four inches long. Seeds are "winged" and grow in cones five or six inches long protected by the scales. Cones mature at end of second season. Wood soft, light coloured, free from sap, easily worked and used in many trades, for pattern making, various parts of houses, toys, crates, boxes, etc. Becoming very scarce, owing to the destruction of the great forests. On the Pacific coast its place in construction is taken by the sugar pine and other woods.
Yellow and Georgia Pine.—Two trees whose wood is frequently confounded by the woodworker. Georgia pine is a tree with very long needles, from twelve to fifteen inches, and in groups of three. Cones from six to ten inches. A southern tree found from Texas to Virginia. The tops of the young trees, like green fountains, are used in many places as Christmas decorations. Wood hard and resinous, used for flooring, interior finish, and decks.
Yellow Pine.—A southern tree with needles in groups of two, sometimes three, about three inches long. Cones small, about two inches. Wood hard and used for the same purposes as Georgia pine.
Red Pine, Norway Pine, Canadian Pine.—Three names for the same tree. Grows throughout the North, from Nova Scotia to western Minnesota. Cut principally in Canada. Needles, two in a group, about five inches long. Cones about two inches long, mature the second season. Wood reddish in colour, hard, and used for piles, spars, bridges, etc.
Pitch Pine.—A name locally given to several different trees. The wood is soft, brittle, resinous, and is used for fuel and for making charcoal, rarely for rough building. Needles in groups of three and three to five inches long. Sometimes called scrub pine, although it often reaches a height of fifty to sixty feet. The cones, two or three inches long, often remain on the tree for years. It is the tree found along the Atlantic coast from Maine to Georgia, growing in sand, in swamps, and among rocks. To be recommended for its persistence in living under the most trying conditions, even if its wood is not very valuable.
In the construction of a frame house several kinds of wood are needed. First, the framework of rough-sawed spruce. Second, a better wood, like white pine, for door and window frames. Third, the outside covering. This may be clapboards, for which nothing has ever approached white pine, although it is necessary now to find substitutes. The roof, if shingled, may be of cedar, or cypress—some spruce is used to-day. For interior work, floors may be spruce, white pine, cypress, yellow pine, or hard woods. For finish or trim, many woods are used such as white wood, oak, yellow pine, cypress, cherry, and bay wood.
Spruce.—This wood has been used almost exclusively in the past for framing, but great inroads have been made in the supply, especially by the manufacturers of paper pulp. Consequently the cost is increasing rapidly.
Three varieties are recognized, white, black, and red. White spruce is a distinctly northern tree, delighting in the cold climate of Canada, but dipping down along the Maine coast. It is a beautiful, straight, and tall specimen, frequently found as high as a hundred and fifty feet. The needles are only three quarters of an inch, or less, in length and clothe the twigs in an entire circle. Cones two inches long, bearing under their scales tiny winged seeds. It is used often as an ornamental evergreen for lawns, and for this purpose probably has no equal, as, unlike the Norway spruce, it holds its foliage, dense and green, close to the ground.
The wood is weak, knotty, and soft, but suitable for rough framing.
Black Spruce.—Another northern tree, rarely found in forests below the Canadian border, except around the Great Lakes.
Leaves about same size as in white spruce, but cones smaller, more oval in form, and one inch and a half long.
Spruce gum is obtained from this tree, which has a more pleasant odour than white spruce.
Wood used for pulp making, framing, and, quartered, for sounding-boards of musical instruments.
Red Spruce.—A close relative of the black and sometimes confused with it, but it is a distinct tree, reaching its best development several hundred miles south of the black spruce, in the Appalachian Mountains, and extending as far south as North Carolina; while the black variety barely crosses the borders of Canada into Maine.
Needles about half an inch long. Cones small, sometimes barely an inch and a half. They fall the first winter, while those of the black remain on the tree often for years.
Wood is similar to black spruce but lighter in weight. Used for pulp, framing, and sounding-boards.
Hemlock.—The most dainty of the eastern evergreens, with little cones about three quarters of an inch long, and needles half an inch. Found throughout the country east of the Mississippi and in some sections used for Christmas decorations.
A slow growing tree with wood of little value, being brittle, light, and difficult to work, as it has a crooked grain and is liable to splinter. The tree makes up in beauty what it lacks as a timber producer and its bark is rich in tannin.
Larch, Tamarack or Hackmatack.—Local names for the same tree. Drops all its needles in the fall, like a broad-leaved tree, but the beauty of the brilliant new green needles in the spring is a sight worth going miles to see.
Found from the Lake states north to the Arctic Circle. Needles an inch long. Cones from one half to three quarters.
Wood is heavy, hard and strong. Used in ship building, for telegraph poles, posts, and ties.
Fir, Balsam Fir, Balsam.—On all firs the cones stand upright on the branches, while on spruces they hang down. As these two trees are often intermingled, this is an easy way to distinguish them. The needles of the firs are also blunt, while those of the spruces are sharply pointed.
This is the so-called Christmas tree and balsam pillows are made from its needles.
Needles about three quarters of an inch long, cones almost black in colour, from two to four inches long.
Wood of little value, being soft and weak.
The sap in the form of gum called Canada balsam is used in medicine, and is obtained from blisters on the bark or by cutting the bark.
Southern Cypress, Bald Cypress, Deciduous Cypress.—Found growing naturally in the swamps of the South, but will grow in drier soil, if planted in the North. Several fine specimens in the parks of Philadelphia, New York, and Brooklyn. The lower part broadens out near the ground into a conical base and in its native swamps the roots send up peculiar formations known as cypress knees.
Leaves very delicate and feathery, not often over half an inch long, cones round and an inch in diameter. Drops its needles like the larch each fall.
Wood very durable in damp situations, valuable for flooring and interior finish.
Red Cedar.—The common cedar of the United States, found in all sections where trees can grow at all, in sand, swamp, rocky hillside, and abandoned farm. Reaches its greatest height in the South.
Wood of beautiful colour and grain, soft and not strong, easily worked, but inclined to brittleness. Used in many trades; it furnished in the past the only wood for lead pencils. Owing to its scarcity, substitutes are now being tried. Very durable in contact with water and soil. Used extensively for posts, small boats, cooperage, ties, chests, and interior finish.
Foliage difficult to describe, being sharp and awl-shaped in the young trees, changing in later years to a flat scale shape. Very often both forms are found on the same tree. Seeds are the common cedar berry, pale green in colour, about a quarter of an inch long, each berry containing two or three seeds. These are liked by the birds and they are dropped along fences frequently, so that in a few years the fences become lined with young cedar trees.
White Cedar.—Found in swamps along the Atlantic and Gulf coasts. Has a more delicate foliage than red cedar, and, growing in dense thickets, is apt to be taller and straighter.
The wood is light brown in colour, soft, weak, and, like red cedar, durable in moist situations. Used for making shingles, for boat-building, and for the same general work as the red variety.
Arbor Vitæ—called in many sections white cedar. It is an entirely different tree from the real white cedar, having decidedly flattened and very aromatic foliage. Used a great deal for hedges before the days of the California privet. Seed borne in a tiny cone half an inch long.
Large quantities are cut in the Maritime Provinces of Canada to be made into shingles. Grows sixty feet high and two feet or more in diameter. Arbor vitæ means tree of life, and as the bark and young twigs were at one time used medicinally, that may have been the origin of the name.
Wood is light, soft, coarse-grained, but, like the cedars, durable. Used for ties, posts, and shingles.
[LVI]
BROAD-LEAVED TREES
The broad-leaved trees are more numerous as to varieties than the evergreens, and from the standpoint of leaf forms may be divided into three groups:
1. Trees bearing simple leaves.
2. Trees bearing compound leaves.
3. Trees bearing doubly compound leaves.
The first group is the largest, including as it does such large families as the maples, oaks, willows, poplars.
The second group comes next with the well-known walnuts, hickories, ashes, and buckeyes.
The third group is very small, there being but three well-known trees bearing doubly compound leaves: the honey locust, Kentucky coffee tree, and Hercules Club.
The three forms are shown at [Fig. 242].
The leaf ends at the bud growing at the end of the leaf stem. All above this bud constitutes the leaf, no matter what its shape or size, and falls in the autumn, with a few exceptions.
The small leaflets on the compound leaf are simply parts of a leaf, not separate leaves, as there are no buds at the point where they join the stem. The arrangement of these leaflets varies. In the buckeye and horse chestnut they radiate from a common point, while in the locust they are in parallel rows on opposite sides of the stem.
Fig. 242. Three types of leaves
In doubly compound leaves the leaflets are themselves compound, making the whole leaf very large, those of the Kentucky coffee tree being three feet in length.