Popular Books on Natural Science by Aaron David Bernstein
Chapter 1 VELOCITIES OF THE FORCES OF NATURE.
In former times, when a man would speak of the rapidity with which light traverses space, most of his hearers thought it to be a scientific exaggeration or a myth. At present, however, when daily opportunity is afforded to admire, for example, the velocity of the electric current in the electro-magnetic telegraph, every one is well convinced of the fact, that there are forces in nature which traverse space with almost inconceivable velocity.
A wire a mile in length, if electrified at one end, becomes in the very instant electrified also at the other end. This and similar things every one may observe for himself; then, even the greatest sceptic among you will clearly see, that the change-or "electric force"-which an electrified wire undergoes at one end, is conveyed the length of a mile in a twinkle, verily as if a mile were but an inch.
But we learn more yet from this observation. The velocity with which the electric force travels is so great, that if a telegraph-wire, extending from New York to St. Louis and back again, is electrified at one end, the electric current will manifest itself at the other end in the same moment. From this it follows, that the electric force travels with such speed as to make a thousand miles in a space of time scarcely perceptible. Or, in other words, it travels a thousand miles in the same imperceptible fraction of a moment that it does a single mile.
And experience has taught us even more yet. However great the distance connected by a telegraphic wire may be, the result has always been, that the time which electricity needs to run that distance, is imperceptibly small; so that it may well be said, its passage occupies an indivisible moment of time.
One might even be led to believe that this is really no "running through"-in other words, that this transmission of effect from one end of the wire to the other end does not require any time at all, but that it happens, as if by enchantment, in one and the same instant. This, however, is not the case.
Ingenious experiments have been tried, to measure the velocity of the elective force. It is now undoubtedly proved, that it actually does require time for it to be transmitted from one place to another; that this certain amount of time is imperceptible to us for this reason, viz., that all distances which have ever been connected by telegraph, are yet too small, to make the time it takes for the current to go from one end to the other, perceptible to us.
Indeed, if our earth were surrounded by a wire, it would still be too short for common observation, because the electric force would run even through this space-twenty-five thousand miles very nearly-in the tenth part of a second.
Ingenious experiments have shown that the electric current moves two hundred and fifty thousand miles in a second. But how could this have been ascertained? And are we certain that the result is trustworthy?
The measurements have been made with great exactitude. To those who are not afraid of a little thinking, we will try to represent the way in which this measurement was taken; although a perfect representation of it is very difficult to give in a few words.
* * *
Chapter 1 VELOCITIES OF THE FORCES OF NATURE.
06/12/2017
Chapter 2 NOTHING BUT MILK.
06/12/2017
Chapter 3 MAN THE TRANSFORMED FOOD.
06/12/2017
Chapter 4 WHAT STRANGE FOOD WE EAT.
06/12/2017
Chapter 5 HOW NATURE PREPARES OUR FOOD.
06/12/2017
Chapter 6 WHAT BECOMES OF THE MOTHER'S MILK AFTER IT HAS ENTERED THE BODY OF THE CHILD
06/12/2017
Chapter 7 HOW THE BLOOD BECOMES THE VITAL PART OF THE BODY.
06/12/2017
Chapter 8 CIRCULATION OF MATTER.
06/12/2017
Chapter 9 FOOD.
06/12/2017
Chapter 10 SOMETHING ABOUT ILLUMINATION.
06/12/2017
Chapter 11 A WONDERFUL DISCOVERY.
06/12/2017
Chapter 12 MAIN SUPPORT OF LEVERRIER'S DISCOVERY.
06/12/2017
Chapter 13 SOMETHING ABOUT THE WEATHER.
06/12/2017
Chapter 14 OF THE WEATHER IN SUMMER AND WINTER.
06/12/2017
Chapter 15 THE CURRENTS OF AIR AND THE WEATHER.
06/12/2017
Chapter 16 THE FIRM RULES OF METEOROLOGY.
06/12/2017
Chapter 17 AIR AND WATER IN THEIR RELATIONS TO WEATHER.
06/12/2017
Chapter 18 FOG, CLOUDS, RAIN, AND SNOW.
06/12/2017
Chapter 19 HOW HEAT IN THE AIR BECOMES LATENT, AND HOW IT GETS FREE AGAIN.
06/12/2017
Chapter 20 LATENT HEAT PRODUCES COLD; FREE HEAT, WARMTH.
06/12/2017
Chapter 21 RULES ABOUT THE WEATHER, AND DISTURBANCES OF THE SAME.
06/12/2017
Chapter 22 THE CHANGEABLENESS OF THE WEATHER WITH REGARD TO OUR GEOGRAPHICAL POSITION.
06/12/2017
Chapter 23 ABOUT THE DIFFICULTY AND POSSIBILITY OF DETERMINING THE WEATHER.
06/12/2017
Chapter 24 THE FALSE WEATHER-PROPHETS.
06/12/2017
Chapter 25 THE RAPID RENEWAL OF THE BLOOD IS AN ADVANTAGE.
06/12/2017
Chapter 26 DIGESTION.
06/12/2017
Chapter 27 COFFEE.
06/12/2017
Chapter 28 COFFEE AS A MEDICINE.
06/12/2017
Chapter 29 USEFULNESS AND HURTFULNESS OF COFFEE.
06/12/2017
Chapter 30 BREAKFAST.
06/12/2017
Chapter 31 LIQUOR.
06/12/2017
Chapter 32 INJURIOUSNESS OF DRINKING LIQUOR.
06/12/2017
Chapter 33 THE POOR AND THE LIQUOR.
06/12/2017
Chapter 34 THE CONSEQUENCES OF INTEMPERANCE AND ITS PREVENTION.
06/12/2017
Chapter 35 DINNER.
06/12/2017
Chapter 36 NECESSITY FOR VARIETY IN FOOD.
06/12/2017
Chapter 37 BROTH.
06/12/2017
Chapter 38 WHAT IS BEST TO BE PUT INTO SOUP
06/12/2017
Chapter 39 LEGUMINOUS VEGETABLES.
06/12/2017
Chapter 40 MEAT AND VEGETABLES.
06/12/2017