Technology & Engineering
Technology & Engineering Books
Sort by:
CHAPTER I ACOUSTICS Telephony is the art of reproducing at a distant point, usually by the agency of electricity, sounds produced at a sending point. In this art the elements of two general divisions of physical science are concerned, sound and electricity. Sound is the effect of vibrations of matter upon the ear. The vibrations may be those of air or other matter. Various forms of matter transmit...
more...
by:
Herman Friedl
Ice for Commercial Purposes ICE for commercial purposes is obtained in two ways: either by cutting during the winter time from our lakes and rivers and storing in large Ice Storage Houses located alongside, or by freezing pure clean water by means of artificial refrigeration. All authorities are agreed that artificial ice is more sanitary than natural ice and it is only a matter of time when the use of...
more...
The year 1913 marks the close of the first fifty years since Abraham Lincoln issued that famous edict known as the emancipation proclamation, by which physical freedom was vouchsafed to the slaves and the descendants of slaves in this country. And it would seem entirely fit and proper that those who were either directly or indirectly benefited by that proclamation should pause long enough at this...
more...
Introduction The art and science of agriculture embrace most intentional human efforts to control biological activity so as to produce plants and animals of the sort wanted, when wanted. Rubber plantations, cattle ranches, vegetable gardens, dairy farms, tree farms, and a host of similar enterprises all represent human efforts to compel nature to serve man. Those who undertake agriculture have had,...
more...
by:
Edward Belcher
CHAPTER I THE EYE OF THE FLEET The fleet of boats and canoes bearing supplies for the far east turned from the Mississippi into the wide mouth of the Ohio, and it seemed, for a time, that they had come into a larger river instead of a tributary. The splendid stream, called by the Indians "The Beautiful River," flowed silently, a huge flood between high banks, and there was not one among the...
more...
MY EXCUSE My sixtieth birthday is a thing of yesterday, and I have, therefore, more than half descended the western slope. I have no quarrel with life or with time, for both have been polite to me; and I wish to give an account of the past seven years to prove the politeness of life, and to show how time has made amends to me for the forced resignation of my professional ambitions. For twenty-five...
more...
CHAPTER I. INTRODUCTION. Our distance from the old world, and the favorable circumstances in which we have been placed with respect to the other nations of the new world, have made it so easy for our government to adhere to a pacific policy, that, in the sixty-two years that have elapsed since the acknowledgment of our national independence, we have enjoyed more than fifty-eight of general peace; our...
more...
INTRODUCTION Since the earliest communities of human beings first struggled for supremacy and protection, the principles of warfare have remained unchanged. New methods have been evolved and adopted with the progress of science, but no discovery, save perhaps that of gunpowder, has done so much in so short a time to revolutionize the conduct of war as aviation, the youngest, yet destined perhaps to be...
more...
CHAPTER I IT IS an old saying that "any fool can farm," and this was almost the truth when farming consisted chiefly in reducing the fertility of new, rich land secured at practically no cost from a generous Government. But to restore depleted soils to high productive power in economic systems is no fool's job, for it requires mental as well as muscular energy; and no apologies should be...
more...
I COMMUNICATION AMONG THE ANCIENTS Signaling the Fall of Troy—Marine Signaling among the Argonauts—Couriers of the Greeks, Romans, and Aztecs—Sound-signaling—Stentorophonic Tube—The Shouting Sentinels—The Clepsydra—Signal Columns—Indian Fire and Smoke Signals. It was very early in the history of the world that man began to feel the urgent need of...
more...