Page:Popular Science Monthly Volume 2.djvu/398

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382
THE POPULAR SCIENCE MONTHLY.

is not at all affected by the presence of the antiseptic. Probably, if 6 per cent, or even 8 per cent, of borax were used with the liquid at about 40° C. at the moment of injection, the cadaver itself having been previously kept for some hours in some warm medium, the borate of ammonia might be omitted. Then an adult cadaver might be prepared at the trifling expense of two francs. For purposes of embalming, the writer recommends a concentrated solution of both salts, injected two or three times into the blood-vessels at intervals of a few days. Pulverized borax would also be of service in preserving the skins of stuffed animals and birds; and the solution might be used instead of alcohol in cases where the latter is now employed to preserve specimens.

 

Disintegration of Tin.—Two cases of the disintegration of tin are given in the American Artisan, the phenomenon being in the one case traceable to the action of intense cold and long-continued vibration, while in the other the cause of the disintegration is unknown. A certain quantity of tin in ingots was shipped from Rotterdam to Moscow by rail during extremely cold weather. On reaching its destination it was found to have been reduced to a powder, with coarse crystalline grains. When fused, instead of forming a solid mass, it gave only oxide of tin, a gray powder. The second case was that of two pigs of "Banca tin," purchased by the United States Ordnance Bureau. They had lain in store for several years; and, when at length they were taken from their resting-place, one was found almost entirely reduced to a gray powder, while the process of disintegration in the other was as yet confined to the edges. Dr. I. Walz, who communicates to the Artisan this piece of information, tried in vain to learn the previous history of these two pigs of tin. It is his belief that the instances here recorded are the only ones known of tin assuming a granular condition.

 

A Squirrel-Pest.—In some parts of Arkansas the squirrels were so numerous the past season that they destroyed entire fields of corn. As many as 125 have been killed by one person in a day.

 

Welding Copper.—According to the Journal of the Franklin Institute, Mr. Rust has succeeded in perfecting a method by which he accomplishes a perfect welding of copper. He mixes together 358 parts of phosphate of soda and 124 parts of boracic acid. This powder is applied when the metal is at a low red heat; it is then brought to a cherry-red, and at once hammered with a wooden hammer.

 

Effect of Atmospheric Pressure.—Mr. Paul Best, in a very interesting memoir, shows that the destruction of life by diminished barometric pressure is chiefly to be attributed to deficiency of oxygen. An animal that will die with the pressure reduced to 18 centimetres (7 inches) of mercury, will endure a reduction to 6 centimetres (2.4 inches) if an additional supply of oxygen be furnished. And the converse is also true, that the danger of too great pressure is from the increased amount of oxygen in a given volume of air inhaled.

 

Relations of Local Diseases to the Nature of the Soil.—Dr. Moffat read before the British Association a paper on the above subject, in which he shows that the nature of the soil exercises considerable influence on the character of endemic disease. His district lies on the carboniferous and red, or Cheshire, sandstone formation. Anæmia is the prevailing condition of the inhabitants of the carboniferous land, who are both miners and farmers, while it is almost unknown on the red sandstone. Consumption is also more prevalent in the first-named district. Since anæmia is a want of iron in the blood, Dr. Moffat examined the constitution of wheat grown on the Cheshire sandstone, and found it produced much more ash, and hence a larger proportion of mineral constituents, including oxide of iron, than that grown on the carboniferous soil. He estimates that a pound of wheat from the first furnishes five grains more of oxide of iron to the consumer than a pound of wheat from the second soil, which accounts for the comparative poverty of the blood of the miners in iron and phosphoric acid. An examination of the blood of the animals kept in the two districts confirmed the above observations.