Page:Popular Science Monthly Volume 8.djvu/521

Rh fires on shipboard was recently patented. This apparatus, the "pyroletor," as it is called, consists of a small double pump worked by hand, which sucks lip through a tube on each side of it strong muriatic acid, and a solution of bicarbonate of soda; these commingle in a generator forming part of the pump, and the carbonic-acid gas and bicarbonate solution pass at once down a metal pipe to the hold, along whose keelson runs a perforated wooden box which admits of the gas passing through to the burning material. The agent, therefore, for the extinction of fire, is dry carbonic-acid gas, which has no action on the cargo. The Chemical News describes as follows an exhibition lately given of the working of the "pyroletor:" "The entire hold of a large wooden barge was covered to a depth of several feet with wood-shavings and cotton-waste saturated with turpentine and naphtha. A temporarily-raised and by no means air-tight wooden deck, with loosely-fitting boards, formed the wide hatchway-covering. The combustible material having been set on fire, the flames immediately ran along the entire cargo and issued above the temporary deck, which was then covered with boarding. The 'pyroletor' having been brought into action, the fire was completely extinguished in four minutes, though nearly half a gale was blowing." It is computed that a 1,200 ton ship requires half a ton of each of the chemicals, costing about $100.

Physical Characters of the British.—Dr. Beddoe, at the recent meeting of the British Association, advocated the necessity, from a practical point of view, not from that of mere scientific curiosity, of obtaining more extensive and accurate information as to the physical characters of man in Britain than could be obtained by private investigations. He desired to inquire thoroughly and systematically into the rates of growth, average stature, weight, etc., of men and women under normal or abnormal conditions, so as to have a fair starting-point for further investigation and action. Lord Aberdare said that some time since it was ascertained that the Irishman was superior to the Scotchman in vigor, and that the Englishman was lowest of the three. This he attributed to the fact that in Ireland and Scotland children were fed on food appropriate to them. He moved that a committee be appointed to collect observations on the subject of the heights and weight of human beings in Great Britain and Ireland, and that a grant of money be made to defray the expenses of such an inquiry. This resolution was adopted.

Native Home of the Rocky Mountain Locust.—In view of the great interest and alarm excited by the ravages of the grasshoppers in the West last year. Prof. C. V. Riley, State Entomologist of Missouri, gives, in the last seventy-five pages of his Seventh Annual Report, a very full and interesting account of the natural history of this insect, including the plants it feeds on, the parasites that feed on it, and a history of its noted incursions, with the means that may profitably be employed to arrest its depredations. From the section on its "native home" we quote some interesting remarks concerning the spread of the insect.

Having in July, 1874, given the opinion that the swarms of that year would reach the western counties of Missouri too late to do serious damage, and that they would not extend eastward beyond a line drawn, at a rough estimate, along longitude 17° west from Washington—an opinion, by-the-way, that was remarkably confirmed by subsequent events—the professor here proceeds to give his reasons for that conclusion:

'But it will be asked, 'Upon what do you base this conclusion, and what security have we that at some future time the country east of the line you have indicated may not be ravaged by these plagues from the mountains?' I answer that, during the whole history of the species, as I have attempted to trace it in the chronological account already given, the insect never has done any damage east of the line indicated, and there is no reason to suppose that it ever will do so for the future. . ..

"'But why,' it will again be asked, 'will not the young from the eggs laid along the eastern limit you have indicated hatch and spread farther to the eastward?' Here, again, historical record serves us, and there are, in addition, certain physical facts which help to answer the question.

"There is some difference of opinion as to the precise natural habitat and breeding-place of these insects, but the facts all indicate that it is by nature a denizen of great altitudes, breeding in the valleys, parks, and plateaus of the Rocky Mountain region of Colorado, and