M. Dumas on the Equivalents of the Elements. 423 



presence of a trace of sulphuric acid in the latter is not injurious. 

 The mixture is heated in the water-bath at a temperature of 

 about 60° C. ; and the flasks are fllled, so that when the expan- 

 sion has taken place the neck is about half full. By this method 

 Schiel has prepared the acid on a scale twenty times as large as 

 that indicated in the books. 



Water absorbs ten or twelve times its volume of chlorous acid ; 

 the solution is of a deep yellowish-red colour, and may be kept 

 for some time without decomposition. It is very valuable as a 

 deodorizer and disinfectant ; its oxidizing power, as compared 

 with that of chlorine, is as 4 : 1 ; it dissolves amorphous phos- 

 phorus almost instantaneously. The most interesting salt is the 

 chlorite of lead, PbO ClO^; this is prepared by nearly neutralizing 

 a solution of the acid with milk of lime, filtering, precipitating 

 the filtrate while warm with nitrate of lead, and washing out the 

 filtrate with distilled water. Mixed with sulphur and exposed 

 to friction, it explodes : it is also remarkable for exploding at the 

 temperature of boiling water. Under certain circumstances it 

 combines with chloride of lead to a double salt of the com- 

 position 3 PbO ClO^, PbCl, which forms pale yellow acicular 

 crystals. Chlorous acid seems to exercise a curious action on 

 organic substances, more especially on urea, albumen, and uric 

 acid ; with the study of these the author is engaged. 



In continuation of his investigations into the equivalent 

 weights of the elements, Dumas* has pointed out further in- 

 teresting relations. 



Among the substances investigated, twenty-two have equi- 

 valents which are exact multiples by whole numbers of that of 

 hydrogen taken as unity : — oxygen, 8 ; sulphur, 16 ; selenium, 

 40; tellurium, 64; nitrogen, 14; phosphorus, 31 ; arsenic, 75 ; 

 antimony, 122; bismuth, 214; fluorine, 19; bromine, 80; 

 iodme, 127; carbon, 6; silicon, 14; molybdenum, 48; tung- 

 sten, 92; lithium, 7; sodium, 23; calcium, 20; iron, 28; cad- 

 mium, 56 ; tin, 59. 



Seven have equivalents which are multiples of half the equi- 

 valent of hydrogen : — chlorine, 85-5 ; magnesium, 12-5 ; man- 

 ganese, 27-5 ; barium, 68-5 ; nickel, 295 ; cobalt, 29-5 ; lead, 

 103-5. 



Three have equivalents which are multiples of a quarter the 

 equivalent of hydrogen: — aluminium, 1375; strontium, 43-75; 

 zinc, 32-75. 



The result of all experiments to revise the equivalents has 

 been to approximate the numbers more and more closely to 

 those given in the Tables. 



* Licbig's /ln/J«/('n, December 1858. Comples Rendus, vol. xlvi. p. !>.^)1. 



