JOURNAL OF CHEMICAL EDUCATION
62
.
JANUARY,
1931
certain physical constants, as our scientists have chosen water, great differences would result. First, the unit of specific heat would not be the same, for 1.13 of our calories would he required to raise the temperature of one gram of ammonia one degree Centigrade. Further, the system of thermometry might well differ. The melting point of ammonia is -77.7' and the boiling point -33.35"; calling the first temperature 0' Ammonia and the latter 100°A., then one degree on the ammonia scale of temperature would equal 0.4435 of a degree Centigrade, and O°C. would be approximately 175'A. Finally, if the physicists on our imaginary ammonia world had chosen to define their unit of weight, an ammonia gram, as the weight of 1 milliliter of ammonia a t some stated temperature-say -4O0then their entire system of weights would differ from our own since ammonia is much less dense than water. Ammonia, however, would be a very poor substance t o serve as a standard for density because its density varies continually with temperature and does not slowly approach toward and descend from a maximum density as does water a t 4". Such then would he some characteristics of an "ammonia w o r l d ; a world essentially similar to our own water world but differing greatly in many respects because of ditferences in the basic substances making up such a world. One might similarly picture a hydrogen sulfide world where the minerals are sulfur compounds and life is built around the element sulfur. Recent studies of sulfur bacteria have revealed organisms which have gone perhaps just a step in this direction.
(1)
~iteratureyited FRANKLIN, Am. Chem. J., 47,255 (1912).
HENDERSON. "The Fitness of the Environment," The Macmillan Co.. New York City, 1927. (3) TART,Trans. Kan. Acad. Sci., 32,38 (1929); FRANCE, WILDER, and RANKIN, private communication.
(2)
Acrolein Makes Refrigerant Safe. The addition of acrolein, an irritating gas used in the World War, to methyl chloride when used in household refrigerators will make it impossible for a person to remain near a leak long enough t o he injured by the poisonous gas, which has in the past caused several deaths. Experiments conducted by the U. S. Bureau of Mines a t Washington a t the request of the manufacturers of electric refrigerators and methyl chloride, indicate that one part of acrolein t o a million p a N of air will produce a decided irritation of the eye and nose in two minutes and will become practically unbearable within five minutes. Exposure t o even a bad leak of methyl chloride for that length of time does not cause apparent harm. Acrolein is that acrid, irritating stuff familiar t o the housekeeper who has ever allowed fat t o spatter on a hot stove or who has forgotten the kerosene lamp and let i t burn low and smolder. I n the chemical laboratory it is made from glycerin.-Science Service
