I. - RESEARCH. 505 



2499. Glass Digester in which to heat substances under 

 pressure. 



The apparatus consists of a well-annealed glass cylinder, closed 

 at one end and drawn out at the other to a tube. Its capacity is 

 about 600 cubic centimetres; the thickness of its walls about 

 l an inch throughout. The tube forming the neck is about 

 | of an inch in bore, and is closed by an accurately ground glass 

 plate. The glass cylinder is mounted in a framework of brass, 

 provided with a screw, which when turned presses the glass 

 plate tightly against the lube, and thus hermetically closes the 

 digester. The apparatus has been employed in the preparation of 

 bromacetic acid, and large quantities of that substance have been 

 prepared by its aid. The digester is intended as a substitute for 

 sealed tubes, and has the great advantage over these that large 

 quantities of substance can be heated at one operation, and that 

 the danger of unsealing is avoided. 



The apparatus is heated in an oil bath. Dr. E. A. Letts. 



2500. Methyl-Sulphate of Calcium. 



Dr. E. A. Letts and Mr. C. Abraham. 



2501. Methyl-sulphate of Zinc. 



Dr. E. A. Letts and Mr. C. Abraham. 



2502. Methyl-sulphate of Ammonium. 



Dr. E. A. Letts and Mr. C. Abraham. 



2503. Specimens of Acetamide,Butyramide,Isobutyramide, 

 and Valeramide ; also of Valero-nitrile and Benzo-nitrile. These 

 have been obtained by the action of the corresponding acids on 

 Rulphocyanate of potash, according to the equation 



R-COOH+KGNS=HCNS + R-COOK. 



+ R-CONH 2 



(In the case of the fatty acids the amide is the principal [pro- 

 duct, whilst the nitrile alone appears to be produced from the acid 

 of the aromatic series. The process is easily and rapidly performed, 

 and the yield good in all cases. 



(See Proceedings of the Royal Society, No. 140, 1873.) ^^ 

 Dr. E. A. Letts and Mr. R. S. Marsden. 



2504. Hyposulphite of Copper, Ammoniun and Sodium, 



obtained by mixing a strong solution of hyposulphite of soda 

 with ammonio-sulphate of copper. The salt separates from the 

 solution spontaneously. Its formula is doubtful. 



Dr. E. A. Letts and Mr. W. J. Nicol. 



2505. Hyposulphite of Magnesium, obtained from hypo- 

 sulphite of strontium by double decomposition with sulphate of 



