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Theodore Roosevelt (1858–1919). Through the Brazilian Wilderness. 1914.

Page 390

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.
  A tape measure with metric scale of measurements on one side and feet and inches on the other is most important. Two small, light waterproof cases could be constructed and packed with scientific instruments, data, and spare clothing and yet not exceed the weight limit of flotation. In transit by pack-train these two cases would form but one mule load.
  PHOTOGRAPHIC.—From the experience gained in several fields of exploration it seems to me that the voyager should limit himself to one small-sized camera, which he can always have with him, and then carry a duplicate of it, soldered in tin, in the baggage. The duplicate need