| Brickwork. The Number of Bricks and Quantity of Brickwork in Wells for each Foot in Depth. (Hurst.) | ||||||
| Half-Brick Thick. | One Brick Thick. | |||||
| Number of Bricks. | Number of Bricks. | |||||
| Laid Dry. | Laid in Mortar. | Cubic Feet of Brickwork. | Laid Dry. | Laid in Mortar. | Cubic Feet of Brickwork. | |
| 1·0 | 28 | 23 | 1·6198 | 70 | 58 | 4·1233 |
| 1·3 | 33 | 27 | 1·8145 | 80 | 66 | 4·7124 |
| 1·6 | 38 | 31 | 2·2089 | 90 | 74 | 5·3015 |
| 1·9 | 43 | 35 | 2·7979 | 112 | 92 | 6·4795 |
| 2·3 | 53 | 44 | 3·0926 | 122 | 100 | 7·0686 |
| 2·6 | 58 | 48 | 3·3870 | 132 | 108 | 7·6577 |
| 3·0 | 68 | 57 | 3·9760 | 154 | 126 | 8·8357 |
| 3·6 | 79 | 65 | 4·5651 | 174 | 142 | 10·0139 |
| 4·0 | 89 | 73 | 5·1541 | 194 | 159 | 11·1919 |
| 4·6 | 100 | 82 | 5·7432 | 214 | 176 | 12·3701 |
| 5·0 | 110 | 90 | 6·3322 | 234 | 192 | 13·5481 |
| 5·6 | 120 | 98 | 6·9213 | 254 | 209 | 14·7263 |
| 6·0 | 130 | 107 | 7·5103 | 276 | 226 | 15·9043 |
| 6·6 | 140 | 115 | 8·0994 | 296 | 242 | 17·0825 |
| 7·0 | 150 | 123 | 8·6884 | 316 | 260 | 18·2605 |
| 7·6 | 160 | 131 | 9·2775 | 336 | 276 | 19·4387 |
| 8·0 | 170 | 140 | 9·8665 | 358 | 292 | 20·6167 |
| 8·6 | 180 | 148 | 10·4556 | 378 | 308 | 21·7949 |
| 9·0 | 191 | 156 | 11·0446 | 398 | 326 | 22·9729 |
| 10·0 | 212 | 174 | 12·2227 | 438 | 360 | 25·3291 |
Good bricks are characterized as being regular in shape, with plane parallel surfaces, and sharp right-angles; clear ringing sound when struck, a compact uniform structure when broken, and freedom from air-bubbles and cracks. They should not absorb more than one-fifteenth of their weight in water.
After making liberal allowance for waste, 9 bricks will build a square foot 9 inches thick, or 900, 100 square feet, or say 2880 to the rood of 9-inch work, which gives the simple rule of 80 bricks = a square yard of 9-inch work.
The resistance to crushing is from 1200 to 4500 lb. a square inch; the resistance to fracture, from 600 to 2500 lb. a square inch; tensile strength, 275 lb. a square inch; weight, in mortar, 175 lb. a cubic foot; in cement, 125 lb. a cubic foot.
Compressed bricks are much heavier, and consequently proportionately stronger, than those of ordinary make.
Storing Well-water.
The reservoirs for storing well-water should be covered with brick arches, as the water is generally found to become rapidly impure on being exposed to the sunlight, principally owing to the rapid growth of vegetation. Various methods have been tried, such as keeping up a constant current of fresh water through them, and a liberal use of caustic lime; but so rapid is the growth of the vegetation, as well as the change in the colour of the water, that a few hours of bright sunlight may suffice to spoil several million gallons. These bad results are completely prevented by covering the reservoirs.
Hints on Superintending Well-work.
The engineer who has to superintend the construction of a well should be ever on the watch to see whether, in the course of the work, the strata become so modified as to overthrow conclusions previously arrived at, and on account of which the well has been undertaken.
A journal of everything connected with the work should be carefully made, and if this one point alone is attended to it will be found of great service both for present and future reference.