D. CHEMISTRY AND METALLURGY. 211 



the course of half an hour. Zinc, amalgamated zinc, alumi- 

 num, iron, lead, and magnesium were also used as reducing 

 agents, but none of them acted as efficiently as cadmium. 

 No experiments were made with the alkali metals. 4 i>, 

 III., xii., September, 1876, 176. 



HYDROCELLULOSE. 



In some of the processes in the arts in which woody fibre 

 is used, as in paper-making, for example, the fibre appears to 

 undergo during the process of manufacture a peculiar trans- 

 formation, by which it is rendered friable. Aime Girard has 

 investigated the matter, and finds that this change is owing 

 to the assumption of a molecule of water by each molecule 

 of the cellulose, thus producing a new body having the com- 

 position C12II22O1J, to which he gives the name of hydro- 

 cellulose. To prepare it some form of purified cellulose, such 

 as carded cotton, is placed in sulphuric acid of 45Baume in 

 the cold for twelve hours. It is then well washed, pressed, 

 and dried. After it is dry, its fibrous character is destroyed 

 by pressure ; rubbing between the fingers converts it into a 

 white powder. Girard supposes that this substance may be 

 formed in the process of bleaching paper-pulp by chloride of 

 lime; and accounts in this way for the peculiar brittleness 

 of certain papers found in commerce. 6 B, LXXXL, Decem- 

 ber, 1875, 1105. 



A NEW OXIDE OF SULPHUR. 



Weber has investigated the cause of the intense blue color 

 which is developed whenever sulphur is allowed to act upon 

 sulphuric oxide or disulphuric acid, and has shown that it is 

 due to an oxide of sulphur hitherto unknown, which he has 

 succeeded in isolating and examining. To prepare it, care- 

 fully dried flowers of sulphur are thrown in small portions at 

 a time into sulphuric oxide containing sulphuric acid. At 

 the instant of contact, the sulphur is converted into dark blue 

 liquid drops which sink to the bottom of the liquid and there 

 solidify. Care should be taken to keep the temperature at 

 15 Centigrade, since below this point the whole liquid solid- 

 ifies, and above it the blue body decomposes. After the op- 

 eration the excess of liquid is poured ofi\, tlie blue crystalline 

 crusts are drained, and the excess of sulphuric oxide driven 



