Page:Popular Science Monthly Volume 62.djvu/101

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THE PROGRESS OF SCIENCE.

small percentage of volatile combustible matter. Commercial anthracite varies from the hard, dry Lehigh with little more than one per cent, to the easily lighted Bernice coals of Sullivan county, Penn., with ten per cent. The Lackawanna and Lykens Valley coals, so much prized for domestic use, are midway between Lehigh and Bernice. The use of hard coal has become so well-nigh universal in the eastern towns and cities that one hardly understands how the community could become accustomed to the use of soft coal; yet the available supply of anthracite in America is so small that, unless some other fuel be discovered, the use of bituminous coal must prevail within seventy-five years at the most. The anthracite fields of Pennsylvania will be exhausted within seventy-five years, even though the annual production should not exceed that of 1901—which is improbable. There is no other deposit of anthracite in the United States, aside from some wholly unimportant patches in North Carolina, New Mexico and Colorado, so unimportant that all combined would yield hardly enough for one year's consumption. Europe has very little anthracite. Most of the Welsh coal is bituminous, the anthracite of the South Wales field being confined to the western end of that field. The Worm basin of Prussia yields perhaps 2,000,000 tons per annum of a semi-anthracite; near Ostrau in the Silesian field and in the Donetz field of south Russia anthracite occurs in moderate quantities; but these are all unimportant. China, however, has vast fields compared with which our Pennsylvania fields are mere dots on the map; there being upward of 40,000 square miles underlain by anthracite coals in Hunan, Honan and East Schansi.

 

BORAX AS A FOOD PRESERVATIVE.

The question of the use of borax and boric acid as food preservatives has attracted much attention of late, especially in Germany, where it has been brought forward as a convenient lever to exclude American food products. The results of different investigators are far from uniform, and the conclusions drawn as to its use are correspondingly at variance with each other. It is generally conceded that as far as regards digestion neither borax nor boric acid have any specific influence, but when considerable quantities are present the alkalinity of the former or slight acidity of the latter may be of some effect. In a similar way they may act as mild irritant poisons, occasioning diarrhœa. With continued use most observers find a loss of weight, which seems to be due to loss of fat in the body, and this may occur, without any symptoms of ill health, when small quantities of borax or boric acid are ingested daily. It is possible that this result might attend the regular use of food products which have been preserved by boric acid. While the quantity of the acid present is usually quite small, it is completely eliminated from the system rather slowly. In doses of three grams, one half was eliminated in the first twelve hours, but from five to nine days were required for the disappearance of the remainder. In this way boric acid might have the effect of a cumulative poison. It is said to be a common practice in this country to preserve butter and meat by packing in a mixture of salt with some borax or boric acid. Such a mixture was the 'rex magnum' largely sold fifteen years or so ago. Recent experiments by Polenske show that fat takes up very little of the borax powder, while meats take up no inconsiderable quantity. American pork was found in one case to have absorbed in its outer portion no less than two per cent, of its weight of borax, while in another case four per cent, was taken up in three weeks. This latter amount may, however, be considered extreme. In this connec-