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Page:Popular Science Monthly Volume 49.djvu/151

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139
FRAGMENTS OF SCIENCE.

Royal Commission on Tuberculosis in Animals the statement is made that 'the withdrawal from dairies of every cow that has any disease whatever of the udder would form some approach to security against the serious danger incurred by man from the use of tuberculous milk, but it would not be an adequate security.' The presence in a dairy of a tuberculous cow, the report says, is a decided source of danger to the public, especially having regard to what has been learned respecting the rapid development of tuberculosis of the udder. Regarding the value of tuberculin injections as a diagnostic agent, the following resolutions were adopted at the International Veterinary Congress held last September, and hence represent the opinions of the foremost veterinarians of Europe: 'No. 1. Tuberculin is a very valuable diagnostic agent and can yield the greatest assistance in combating tuberculosis. There is no reason for objecting to its general application on the ground that it may aggravate pre-existing tuberculous lesions. No. 2. The congress expresses the desire that governments shall order the employment of tuberculin in herds in which the existence of tuberculosis has been established.' The official veterinarians of Germany are advised to use tuberculin, and are supplied with it at a low cost from the government laboratories."

 

Tibetan Women.—As described by Mr. W. W. Rockhill, the Tibetan women are usually stouter than the men, with fuller faces, and do not entirely lose their good looks before they are thirty or thirty-five years old. They are as strong as or perhaps even stronger than the men, because, being obliged to do hard work from childhood, their muscles are more fully developed than those of the men, who do not carry water on their backs, work at the loom, or tend the cattle. Their hair is long and coarse, but not very thick; it remains black, or only mixed with a little white, to extreme old age; and both men and women with white hair are rarely seen. The skin of the Tibetan is coarse and greasy, light brown in color, frequently nearly white, except when exposed to the weather, when it becomes a dark brown, nearly the color of our American Indians. Rosy cheeks are common among the younger women. The Tibetans' voices are powerful, those of the men deep, those of the women full and not very shrill. Their hearing is good, and they can converse freely from one side of a valley to the other, a distance of half a mile, without ever having to repeat phrases or perceptibly raise the voice. They can endure exposure without any apparent inconvenience, the women doing their work with the right side of the body completely exposed, and small children going naked, or with only a pair of boots on, except in the coldest weather. They can also endure hunger, and are at all times small eaters.

 

A New Glass Construction.—We take the following from a report presented by Dr. Schott to the French Society for the Encouragement of National Industry: For siliceous glasses the expansion increases with the proportion of alkali. Boric acid produces a striking decrease of expansion. In superposing upon each other two glasses of different compositions, it is requisite that there should exist a certain relation between the relative thickness of the two layers of glass and their coefficients of expansion. Thus at Jena they solder normal thermometer glass, the coefficient of cubic expansion of which between 0° and 100° = 0·0000244, to an aluminous sodium borosilicate, the expansion of which = 0·0000177. The former kind of glass must be placed externally and the second internally in order to form a hollow vessel or tube. We may also join together three or more layers of two or more glasses. Of two layers of glass with different expansions after cooling, that with the greatest expansion will be in a state of tension and the other in a state of compression. External layers in a state of compression increase in a striking manner the resistance of glass to mechanical actions and to rapid changes of temperature. Flasks thus manufactured may be strongly heated (to a temperature of 184°), and may then be sprinkled with cold water without injury. Such glasses are not liable to the sudden rupture which is apt to occur in glass tempered by the process of De la Bastie.

 

An African Village Scene.—"I doubt," says Dr. D. Kerr-Cross, "if finer villages or better built houses exist anywhere in un-