Technology & Engineering Books

DEFINITIONS DEFIN. I. By the Rays of Light I understand its least Parts, and those as well Successive in the same Lines, as Contemporary in several Lines. For it is manifest that Light consists of Parts, both Successive and Contemporary; because in the same place you may stop that which comes one moment, and let pass that which comes presently after; and in the same time you may stop it in any one... more...

CHAPTER ONE THE DEVELOPMENT OF ELECTRICITY The phenomenon which Thales had observed and recorded five centuries before the birth of Christ aroused the interest of many scientists through the ages. They made various practical experiments in their efforts to identify the elusive force which Thales had likened to a 'soul' and which we now know to have been static electricity. Of all forms of... more...

First Dream. "Any fool can get into a hole."—Old Chinese proverb. "If left to you, for defence make spades."—Bridge Maxim. I felt lonely, and not a little sad, as I stood on the bank of the river near Duffer's Drift and watched the red dust haze, raised by the southward departing column in the distance, turn slowly into gold as it hung in the afternoon sunlight. It was just... 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...

CHAPTER I. THE APPARATUS. To a proper comprehension of the succeeding chapters, it is necessary first of all to be familiar with the apparatus employed in carrying out electro-balneological treatment, and I therefore proceed to give a description of this. It may conveniently be divided as follows, viz. a. The tub; b. The electrodes and connections; c. The water; d. Chemicals; e. The batteries. (a) The... more...

Since its first publication "Agriculture for Beginners" has found a welcome in thousands of schools and homes. Naturally many suggestions as to changes, additions, and other improvements have reached its authors. Naturally, too, the authors have busied themselves in devising methods to add to the effectiveness of the book. Some additions have been made almost every year since the book was... 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...

DESCRIPTIVE CATALOGUE OF PLANTS. 1. Abelmoschus moschatus.—This plant is a native of Bengal. Its seeds were formerly mixed with hair powder, and are still used to perfume pomatum. The Arabs mix them with their coffee berries. In the West Indies the bruised seeds, steeped in rum, are used, both externally and internally, as a cure for snake bites. 2. Abrus precatorius.—Wild liquorice. This twining,... more...