104 SCIENCE. [1899.
The optically active substances have the composition NaKC 4 H 4 6 +4H 8 O, whilst that of the racemate is NaKC 4 H 4 6 +3H,0.
In conformity with their molecular proportions, 47*4 grams of sodium potassium dextrotartrate, mixed with 44-4 grams of the race- mate, was dissolved in water and fractionally crystallised as before. The successive separations decreased in specific rotatory power, and it was proved that 1-26 grams of the racemate were resolved, whilst the residue became laevo-rotatory. It is also found that when a half molecular proportion of ammonium dextro-a-bromocamphorsulphon- ate is added to a solution of one molecular proportion of racemic tetrahydroparatoluquinaldine hydrochloride, the Isevo-base separates as the bromocamphorsulphonate.
The conclusion seems to be that a racemic compound may be resolved into its optically active components by simple crystallisation at tem- peratures at which the racemic compound is more stable than a mere mixture of the two optically active salts. But such a resolution has not yet been shown to have occurred in the laboratory of inorganic nature, and Professor Japp, who regards chemists as macro-organisms, may still reply that what only life has joined together only life can put asunder.
The presence in the atmosphere of helium, neon and crypton, is confirmed. M. Gautier, too, alleges that free hydrogen exists in the air in a proportion varying from 11 to 18 cc. in 100 litres.
Helium is associated with particular minerals; these are not, on microscopic examination, found to possess cavities; in some cases a development of heat accompanies the liberation of the gas ; and the quantity obtained from cleveite by treatment with sulphuric acid in an exhausted tube is double that obtained by merely heating the mineral. Hence Mr. Travers considers that helium exists in a state of binary combination, and is evolved according to the equation XHe,=XHe + He. He further supposes that the gas, under the action of sulphuric acid, comes off as an unstable hydride.
Sir Norman Lockyer concludes from his examination of cleveite gases that certain spectral lines closely associated with, are yet distinct from, those of helium, and belong to something new, which he proposes to call asterium, because he finds it present in the hottest stars. The same observer, after a careful study of " series " in spectra, is of opinion that oxygen is not an elemental body, but " is one of the most complex things that we are brought face to face with."
In periodic systems argon is placed among inert substances. Some activity, however, it must be allowed to possess. Its density is 19-957, its refractivity 0-9666, its boiling point -187° C. Submitted to the silent electric discharge in the presence of members of the benzene series, argon is absorbed in amounts varying from 1 to 8 per cent, and a greenish fluorescence appears which has a characteristic spectrum. By similar means M. Barthelot has produced a compound that he calls phenylmercurargon.
In stars of decreasing temperature, the order of the appearance of chemical elements does not, from Sir Norman Lockyer's point of view, correspond with their order in the periodic scheme. He suggests that calcium and magnesium are polymerisations ; that their real order, as
