X.—Tables for the calculation of vapour-density determinations
Journal of the Chemical Society (Resumed)
IF under the head of vapours we include gases, there are several tables which may he used for lessening the labour of calculating a vapour-density. There is one by G e r h a r d t * giving approximately the values of the expression 760 (1 + 0-00367 T) for every integral value of T frorri 0 to 30. There is another by B u n s e n t indicating the vaIues of I + 0-00366 T and log. (1 + 0.00366 ' T' ) €or every T = 0.1 from -2 t o + 40. m e r e is also a table calculated by Mr. G r e v i l l e
... r e v i l l e Williams, giving the values of the for every T = 1 from 0 to 150; and for mula lastly G e r h a r d t t gives the values of log. (1 + 0-00367 T) for every integral value of T from 0 to 299. But 1: found that by substituting the weight of a cubic centirnetre of air for that of a cubic centimetre of nitrogen in the formula with which I headed a table for the calculation of direct nitrogen determinations, I obtained an expression which occurs three times in the formula €or the determination of a vapour-density according to the method of Dumas. For in this formula, which is generally written-1 1 + 0-00367 T P' -P + pp' 1 + k (Tt))v ' ] 1 H 1 + 0.00367 'I"r60 D = but which, written without any abbreviation and modified, becomes * Gerhardt, Trait6 de Chimie Organique, rol 1, page 50. t Bunsen's Gasomtry, translated by Roscoe, page 268. Cerhardt, vol 1, page 115.