Page:Popular Science Monthly Volume 5.djvu/525

Rh is even more remarkable than the descent off the American coast. Fifty miles from Honolulu soundings gave 498 fathoms; 40 miles farther east, in latitude 21° 43' north, longitude 156° 21' west, the depth was 3,023 fathoms. Between the last-mentioned point and that of greatest depth a hill rises, on whose summit there are only 2,488 fathoms of water.

The Origin of Hair-Snakes.—Dr. Slack, in the Turf, Field, and Farm, satisfactorily answers the question put by a correspondent, as to the origin of the so-called hair-snake or hair-worm. The common belief is that these creatures are a transformation of a horse-hair that has remained for some time in water. "When a walking-stick," says Dr. Slack, "becomes a snake, a horse-hair will become a worm. As the former miracle has not taken place since the departure of the Israelites from Egypt, it is safe to conclude that the latter transformation has not recently been made. A dry hair placed in water will absorb the moisture, and, from the unequal expansion of the exterior and interior layers, will become contorted; so too, would a piece of two-inch rope, yet we have never heard of the latter having been accused of possessing vitality. The hair-snake is a living creature, endowed with organs of locomotion and respiration, and capable of propagating its species. Scientifically it is known as Gordius aquaticus, the generic name being derived from the Gordian knot, in allusion to the tangled appearance often presented by a multitude of these animals. The specific name aquaticus is not so appropriate, for they thrive out of water." Dr. Slack has taken Gordii six inches in length from the body of a grasshopper. They have also been found in the stomachs of insectivorous birds.

Cast and Wrought Iron Stoves.—A commission of the French Academy of Sciences has been investigating the hygienic effects of the use of cast-iron stoves. Experiments were made with stoves of wrought and cast iron, using soft coal, with the view of learning under what conditions stoves of metal became unhealthy, through the presence of carbonic acid and carbonic oxide, in the rooms heated by them. Rabbits were made to breathe the air passing over stoves of cast and wrought iron heated to redness, and afterward the blood of the animals was chemically examined, to ascertain the presence of carbonic oxide. The report states that, though the results of experiments made upon rabbits do not enable us to fix with precision the proportion of carbonic oxide absorbed by their blood, nor that of the oxygen which has been expelled from it, still they show that the use of cast-iron stoves, at a red heat, causes in the blood, by the presence of carbonic oxide, a gas eminently poisonous, changes whose repetition may become dangerous; while the same method of investigation has not revealed analogous effects from stoves of wrought-iron. In summing up the results of the entire series of experiments the commission reports as follows:

"The carbonic oxide, whose presence has been proved when stoves of cast iron are used, may arise from several different causes: 1. The permeability of the stove by that gas, which will pass from the interior of the fire-pot to the exterior. 2. The direct action of the oxygen of the air upon the carbon of the cast-iron heated to redness. 3. The decomposition of carbonic acid contained in the air by its contact with metal heated to redness. 4. The influence of the organic dust naturally contained in the air." The commission recommend that all stoves and heating apparatus of cast-iron, and even of wrought-iron, be lined with fire-brick, or other substance, so as to prevent their attaining a red heat.

South-Sea Surgery.—In some of the South-Sea Islands a method of surgical treatment is adopted in certain cases which would bear away the palm, as a torturing process, even from the dreaded moxa. The following description of the South-Sea operation is from the London Medical Times: "The wise men in these islands have invented a theory that headache, neuralgia, vertigo, and other affections of the head, arise from a crack in the skull, or from pressure of the skull upon the brain. The remedy which they have contrived consists in laying open the scalp by a T-shaped incision, and then gently scraping away the cranium itself with a piece of glass until the dura mater