Page:Popular Science Monthly Volume 27.djvu/148

136 "Does any one believe seriously that a cannon-ball can be shot from the earth to the moon? But what harm is there ill letting a child entertain a fancy of the kind for a few hours? He amuses himself with it, and, while he is amused, he learns, without conscious effort, that the moon revolves around the earth, and the earth around the sun, and that there are forces of gravitation and universal attraction, etc. . . . The false idea does no harm, for nothing is built upon it. . . . I venture to say that it is advantageous to inspire children with the love of hazardous adventures, and the taste for the unknown that they find in all the romances of Jules Verne. They will encounter real difficulties soon enough to be discouraged from them earlier than they need to be. Not to see the difficulties is sometimes a good way to triumph over them. We have all grown timid and hesitating, and it is not a bad thing for us to be roused up to ardor in chimerical enterprises, in which the power of science is exhibited to us in the service of an energetic will. It is, perhaps, on this account, as much as for the amusement they give us, that we avow a strong liking for all of M. Verne's works. We might, if it were worth while, defend M. Verne on other considerations. When an idea enters the mind of a child, what matter is it how it gets there? Whether it be in a romance, or in a lesson, or in a text-book, or in a familiar conversation, makes but little difference, so the result is acquired. To tell a fourteen year-old boy that the diamond is crystallized carbon, and that fruitless efforts have been made to produce it artificially, is all very well, but will he remember it? Are these abstract facts interesting enough to stay? Possibly; but the contrary is probable. When you interest a child by relating to him the adventures of Cyprian, as he puts earth and charcoal into a crucible, and tries to crystallize it into a diamond, the scientific fact will not be forgotten; and some day Cyprian will retire into the background, while the physical fact will be a permanent acquisition, which he will owe to this new mnemonic agency. It is more than mnemonics. While M. Verne entertains us with adventures, and fastens scientific facts upon us, he also gives us a taste for science. With him it is a goodly personage, smiling, affable, pleasant, greeting all who come."

Crickets and "Hair-Snakes."—The so called horse-hair snake, as is known to naturalists, is a parasite of the cricket, which only becomes active under water. Dr. H. C. McCook recently read a statement before the Academy of Natural Sciences of Philadelphia which indicates that the crickets are aware of the peculiarity of their parasites, and take advantage of it to get rid of them. A lady having moved into a house which was a harbor for crickets, was troubled by frequently finding the hair-snakes in her water-pails, a short time after the water had been brought into the house. She sat down to watch how they came there. In a short time she saw "a particularly plethoric cricket" mount upon the edge of the pail, and, after some uneasy movements, bring the tip of the abdomen just beneath the water, and, with a few violent throes, expel a black mass, which fell slowly through the water, and, before it reached the bottom, resolved itself into one of the worms. The cricket seemed much exhausted by the operation.

Toxic Effects of Smoking.—Dr. Zulinski, of Warsaw, has made some experiments upon the effects of tobacco-smoke, which he determined to be a distinct poison, even in small doses. Its action on men is very slight when it is not inhaled in large quantities, but it soon becomes powerful in those who contract the habit of "swallowing the smoke." The toxical property is not due exclusively to the nicotine, but the smoke, even when disengaged from nicotine, contains a second toxical principle, called solanine, besides carbonic oxide and hydrocyanic acid. The effects produced by smoking depend upon the nature of the tobacco and the way in which it is smoked. The cigar-smoker absorbs more poison than the cigarette-smoker, and he than the person who smokes a pipe; while the one who uses a medium, by which the smoke is conducted through water, reduces the deleterious effects to a minimum. As a rule, the light-colored tobaccos are supposed to be the mildest, but they are sometimes artificially uncolored by chemicals, the presence of which is