Chemistry and Physics. 481 



the deviation of the F line, (say), will have been changed bv 

 — 10 ,/ Xl-13= — 11-3". That Is, the deviation of the F line 

 is now 41° 51/ 36". The reduction from the new to the stand- 

 ard angle is of course the reverse of this, and that the use of 

 the table saves much labor in redetermining the constants of 

 the prism will be understood when it is added that ours has 

 been entirely refigured and repolished by the maker. as many 

 as ten times during the present year. 



SCIENTIFIC INTELLIGENCE. 



I. Chemistry and Physics. 



1. On the Reaction of Barium sulphate on Sodium carbonate, 

 under pressure. — Spring has succeeded in effecting by means of 

 pressure alone, a reaction between barium sulphate and sodium 

 carbonate. An intimate mixture was made of one part of pure 

 precipitated barium sulphate, thoroughly dried, with three parts of 

 pure and dry sodium carbonate. About a gram of the mixture 

 was submitted to the compression, the cylinder produced pulver- 

 ized and extracted with water ; and the insoluble residue analyzed 

 to determine the amount of barium carbonate produced. After 

 compressing the mixture under a pressure of 6,000 atmospheres for 

 a few instants only, nearly one per cent of the barium sulphate 

 had been transformed into carbonate. The uncompressed mix- 

 ture gave only traces of barium carbonate. The cylinder from 

 the first compression was pulverized and compressed anew. After 

 four successive compressions the amount of carbonate produced 

 rose to 4-78 per cent, and after six to 8-99 per cent, thus showing 

 very clearly the value of renewing the surfaces of contact. If 

 these cylinders after pressure be left to themselves for some time, 

 the chemical action continues up to a period of fourteen days ; 

 the quantity of barium carbonate, produced in the cylinder sub- 

 mitted to six compressions, rising during this time to 10'89 per 

 cent, thus throwing some light on the interesting question of 

 diffusion in solids. Again, if these cylinders, after compression, 

 be divided in halves and one half heated for three houys to 120°, 

 it is found on analyzing these two halves that the barium carbo- 

 nate formed has actually diminished during the heating; the per- 

 centage falling between one and two per cent. The author 

 proposes now to study the reaction of sodium sulphate and barium 

 carbonate under the same conditions. — Bull. Soc. Oh., II, xliv, 

 166, Sept., 1885. g. f. b. 



2. On Sulphocyanuric acid. — The ready conversion of cyanic 

 into cyanuric ether, led Hofmann to attempt a similar transforma- 

 tion with sulphocyanic ether. And successfully, for. on heating 

 methyl sulphocyanate to 180°- 185° for several hours it was con- 

 verted into methyl sulphocyanurate, proved to be the normal 



