Technology & Engineering Books

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...

Advantages of Common-Battery Operation. The advantages of the common-battery system of operation, alluded to in Chapter XIII, may be briefly summarized here. The main gain in the common-battery system of supply is the simplification of the subscribers' instruments, doing away with the local batteries and the magneto generators, and the concentration of all these many sources of current into one... more...

FOREWORD Once in awhile, maybe, twenty-five or thirty years ago, they used to pack you off during the holidays for a visit on Somebody's Farm. Have you forgotten? You went with your little round head close clipped till all the scar places showed white and you came back with a mat of sunbleached hair, your face and hands and legs brown as a nut. Probably you treasure recollections of those boyhood... more...

INTRODUCTORY Electricity, like every science, presents two phases to the student, one belonging to a theoretical knowledge, and the other which pertains to the practical application of that knowledge. The boy is directly interested in the practical use which he can make of this wonderful phenomenon in nature. It is, in reality, the most successful avenue by which he may obtain the theory, for he learns... 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...

FACTS AND OBSERVATIONS ON THE SALMON. In the following observations I intend to offer some remarks on the various migratory fish of the genus Salmo; and then some facts and opinions which tend to show the importance of some change in the laws which are now in force regarding them. We have first the Salmon; which, in the Ribble, varies in weight from five to thirty pounds. We never see the fish here... more...

Induction of Electric Currents. 6. About twenty-six feet of copper wire one twentieth of an inch in diameter were wound round a cylinder of wood as a helix, the different spires of which were prevented from touching by a thin interposed twine. This helix was covered with calico, and then a second wire applied in the same manner. In this way twelve helices were superposed, each containing an average... more...

CHAPTER I. EVOLUTION OF TWO-SURFACE FLYING MACHINE. By Octave Chanute. I am asked to set forth the development of the "two-surface" type of flying machine which is now used with modifications by Wright Brothers, Farman, Delagrange, Herring and others. This type originated with Mr. F. H. Wenham, who patented it in England in 1866 (No. 1571), taking out provisional papers only. In the abridgment... more...

THE FRANCO-AMERICAN CORPS It was on a cool, starlit evening, early in September, 1916, that I first met Drew of Massachusetts, and actually began my adventures as a prospective member of the Escadrille Américaine. We had sailed from New York by the same boat, had made our applications for enlistment in the Foreign Legion on the same day, without being aware of each other's existence; and in... more...

HISTORY OF FARMINGThe Land and the People From the most southern point of Ontario on Lake Erie, near the 42nd parallel of latitude, to Moose Factory on James Bay, the distance is about 750 miles. From the eastern boundary on the Ottawa and St Lawrence Rivers to Kenora at the Manitoba boundary, the distance is about 1000 miles. The area lying within these extremes is about 220,000 square miles. In 1912... more...