PDF Books in Astronomy Science
Tractor Principles
by Roger B. WhitmanThe tractor of to-day is built in almost as many types and designs as there are tractor makers, and is far from being as standard as the automobile. There are tractors with one driving wheel, with two driving wheels, with three and with four, as well as three arrangements of the crawler principle; there are two-wheelers, three-wheelers and four-whe..
Hints to Travellers, Scientific and General, Vol. 2
by Royal Geographical SocietyThe minimum requirement of instrumental observations by a traveller is the reading twice daily of the barometer and of the dry and wet bulb thermometers, to ascertain the temperature and humidity of the air, also the reading once daily, in the morning, of the minimum thermometer which has been exposed all night, and on days in camp of the maximum t..
The Wright Brothers
by Fred C. KellyTHE aim in this book has been to satisfy the curiosity of the average, non-technical reader regarding the work of the Wright Brothers, and to do so as simply as possible. No attempt has been made to go into minute technical details. Nor does the book cover the scientific researches and numerous inventions by Orville Wright since the death of his br..