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Showing: 21-30 results of 59

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 length of wire of twenty-seven feet, and all in... 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 the abstract more readily from concrete... more...

PREFACE "Let posterity know, and knowing be astonished, that on the fifteenth day of September, 1784, Vincent Lunardi of Lucca, in Tuscany, the first aerial traveller in Britain, mounting from the Artillery Ground in London, and traversing the regions of the air for two hours and fifteen minutes, on this spot revisited the earth. In this rude monument for ages be recorded this wondrous enterprise successfully achieved by the powers of chemistry... more...

FOREWORD We are not tied to a desk or to a bench; we stay there only because we think we are tied. In Montana I had a horse, which was hobbled every night to keep him from wandering; that is, straps joined by a short chain were put around his forefeet, so that he could only hop. The hobbles were taken off in the morning, but he would still hop until he saw his mate trotting off. This book is intended to show how any one can trot off if he... more...

ANNOUNCER In the year 1661 Connecticut received from the hand of Charles the Second a very liberal charter granting to the people of the colony almost complete self-government and to the colony an enormous stretch of territory extending westward to the Pacific Ocean. For fifteen years the colony prospered under the generous charter. Then in 1676 trouble arose with the Governor of New York, Sir Edmund Andros, about the boundary line between the... more...


Introduction This report has been undertaken for a special reason. It is to explain to the taxpayer just why so many of his dollars are going into the American effort to explore space, and to indicate what he can expect in return which is of value to him. Such an explanation, even after 2 years of relatively high-geared activity in the space exploration field, appears to be warranted. There is still a segment of the U.S. population which has... more...

Chapter I. INTRODUCTION. In the last three hundred years there have been many questions of general interest before the American people. It is doubtful, however, if there is another problem, which is as warmly debated to-day as ever and whose solution is yet so uncertain, as that of the Negro. In the second decade of the seventeenth century protests were being filed against black slavery, but the system was continued for nearly 250 years. The... more...

CHAPTER I. Man's Duel with Nature Of all man's great achievements none is, perhaps, more full of human interest than are those concerned with flight. We regard ourselves as remarkable beings, and our wonderful discoveries in science and invention induce us to believe we are far and away the cleverest of all the living creatures in the great scheme of Creation. And yet in the matter of flight the birds beat us; what has taken us years of... more...

CHAPTER I Introduction to Plants Our object in reading and studying this book is to find out some facts that will help those of us who are thinking of going into farming and gardening as a business or recreation to start right, and will also help those of us that are already in the business to make our farms and gardens more productive. In order to make the book of greatest value to you, I would urge you not only to read and study it, but... 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 years, up to 1895, I practised medicine and... more...