VOL.8, No. 1
DISTILLATION OF SOFT COAL
151
second, containing lime, will collect the acidic vapors of carhon dioxide and hydrogen sulfide. (b) Instead of lime, sulfuric acid may he used in the second test tube (Figure 3). The acid, of course, will combine with the ammonia, which later can be driven off by heating with lie. The presence of ammonia in coal gas can thus be very satisfactorily demonstrated. Shelled Nuts Often Form Soap Deposits in Glass Containers. The mystery of the frostlike deposit frequently seen on the inside of glass jars containing shelled pecans, or other nuts, has been solved by E. K. Nelson and H. H. Mottern, Bureau of Chemistry and Soils. The deposit is soap, these chemists say, and it is formed by the action of the acid fat of the nuts on the alkali of the glass. It causes a financial Ioss in the sale of the product. The unexplaimed presence of the Soapy -.deposit has long been a source of annoyance to packers of shelledmts and to some housewives in the South who put up shelled pecans in glass jars when the nuts are plentiful and inexpensive. Althou~hthe soap does not impair the quality of the nuts, i t presents an unsightly appearance and reacts against the sale cf the product. When the problem was presented to the chemists for solution, their k t thought wss that the jars might have been washed with an alkaline cleaner and that somp of the alkali remaining on the glass had come in contact with the acid fat of the nuts and produced the chemical change common in soap manufacture. Study proved this theory incorrect, however. Further investigation showed that shelled nuts packed in ordinary glass containers formed the white deposit, whereas nuts put up in hard-glass containers a t the same time and under the same conditions formed no deposit. It was concluded. therefore, that the soap was fonned by the action of the nut fat on the gMs.-The OficiaJ Record ~
Some Bacteria Breathe Hydrogen, Not Oxygen. Bacteria that find oxygen, the very breath of life to most organisms, to be a rank poison and that breathe hydrogen instead, have had their physiological secrets investigated by Prof. J. W. McLeod of the University of Leeds school of medicine. Prof. McLeod presented his findings a t the Fifth International Botanical Congress, recently held a t Cambridge, England. Plants and animals take up oxygen simply as the readiest means of obtaining energy from food substances. These bacteria, which prefer places where there is little or no air, are able to get their needed energy by a different process. They detach hydrogen from certain complex organic compounds, and the brealring apart of these molecules releases energy. Oxvnen is inimical to this ~rocess. If the newly released hvdronen . - comes into contaci&th oxygen the two elements unite to form hydrogen peroxide. Bacteria that can live in the presence of a very little air can tolerate a certain low concentration of hydrogen peroxide, but those that demand surroundings where there is no oxygen a t all apparently find themselves . paralyzed if hydrown is generated even in small . peroxide . quantities. A curious fact about these oxygen-hating bacteria is that they are quite lacking in one of the enzymes or organic ferments, catalase. This particular enzyme was once thought to be absolutely indispensable to any kind of life.-Science Sewice ~
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