Through the Brazilian Wilderness

by Theodore Roosevelt

There are little personal conveniences which sometimes grow into necessities. One of these in my own case was a little electric flash- light taken for the purpose of reading the verniers of a theodolite or sextant in star observations. It was used every night and for many purposes. As a matter of necessity, where insects are numerous one turns to the protection of his hammock and net immediately after the evening meal. It was at such times that I found the electric lamp so helpful. Reclining in the hammock, I held the stock of the light under my left arm and with diary in my lap wrote up my records for the day. I sometimes read by its soft, steady light. One charge of battery, to my surprise, lasted nearly a month. When forced to pick out a camping spot after dark, an experience which comes to every traveller in the tropics in the rainy season, we found its light very helpful. Neither rain nor wind could put it out and the light could be directed wherever needed. The charges should be calculated on the plan of one for every three weeks. The acetylene lamp for camp illumination is an advance over the kerosene lantern. It has been found that for equal weight the carbide will give more light than kerosene or candle. The carbide should be put in small containers, for each time a box is opened some of the contents turns into gas from contact with the moist air.

TOOLS—Three or four good axes, several bill-hooks, a good hatchet with hammer head and nail-puller should be in the tool kit. In addition, each man should be provided with a belt knife and a machete with sheath. Collins makes the best machetes. His axes, too, are excellent. The bill-hook, called foice in Brazil, is a most valuable tool for clearing away small trees, vines, and under-growths. It is marvellous how quickly an experienced hand can clear the ground in a forest with one of these instruments. All of these tools should have handles of second-growth American hickory of first quality; and several extra handles should be taken along. The list of tools should be completed with a small outfit of pliers, tweezers, files, etc.—the character, of course, depending upon the mechanical ability of the traveller and the scientific instruments he has with him that might need repairs.

SURVEY INSTRUMENTS—The choice of instruments will depend largely upon the character of the work intended. If a compass survey will suffice, there is nothing better than the cavalry sketching board used in the United States Army for reconnaissance. With a careful hand it approaches the high degree of perfection attained by the plane-table method. It is particularly adapted for river survey and, after one gets accustomed to its use, it is very simple. If the prismatic compass is preferred, nothing smaller than two and one half inches in diameter should be used. In the smaller sizes the magnet is not powerful enough to move the dial quickly or accurately.

Several good pocket compasses must be provided. They should all have good-sized needles with the north end well marked and degrees engraved in metal. If the floating dial is preferred it should be of aluminum and nothing smaller than two and one half inches, for the same reason as mentioned above regarding the prismatic compass.

Expense should not be spared if it is necessary to secure good compasses. Avoid paper dials and leather cases which absorb moisture. The compass case should allow taking apart for cleaning and drying.

The regular chronometer movement, because of its delicacy, is out of the question for rough land or water travel. We had with us a small- sized half-chronometer movement recently brought out by the Waltham Company as a yacht chronometer. It gave a surprisingly even rate under the most adverse conditions. I was sorry to lose it in the rapids of the Papagaio when our canoes went down.

The watches should be waterproof with strong cases, and several should be taken. It would be well to have a dozen cheap but good watches and the same number of compasses for use around camp and for gifts or trade along the line of travel. Money is of no value after one leaves the settlements. I was surprised to find that many of the rubber hunters were not provided with compasses, and I listened to an American who told of having been lost in the depths of the great forest where for days he lived on monkey meat secured with his rifle until he found his way to the river. He had no compass and could not get one. I was sorry I had none to give; I had lost mine in the rapids.

For the determination of latitude and longitude there is nothing better than a small four or five inch theodolite not over fifteen pounds in weight. It should have a good prism eyepiece with an angle tube attached so it would not be necessary to break one's neck in reading high altitudes. For days we travelled in the direction the sun was going, with altitudes varying from 88° to 90°. Because of these high altitudes of the sun the sextant with artificial horizon could not be used unless one depended upon star observations altogether, an uncertain dependence because of the many cloudy nights.

BAROMETERS—The Goldsmith form of direct-reading aneroid is the most accurate portable instrument and, of course, should be compared with a standard mercurial at the last weather-bureau station.

THERMOMETERS—A swing thermometer, with wet and dry bulbs for determination of the amount of moisture in the air, and the maximum and minimum thermometer of the signal-service or weather-bureau type should be provided, with a case to protect them from injury.