484 Miscellaneous Intelligence, 



lution of borax be not higher than 1.170, then only ordinary crys- 

 tals are obtained 3 so that one or the other may be procured at 

 pleasure. 



M. Payen then proceeded to ascertain the atomic weight of bo- 

 .racic acid, and of some borates in various states. Weighed portions 

 of pure and anhydrous borax were dissolved in water and con- 

 verted into both crystallized forms, and the increase of weight 

 ascertained : 100 parts of prismatic borax were found to contain 

 46.95 of water j and 100 parts of octoedral borax, 30.64 of water. 



Then boracic acid was purified by repeated crystallizations, and, 

 ultimately, fused : subcarbonate of soda was also prepared with 

 the utmost care, by crystallization and conversion into bicarbonate, 

 and then fuzed. A given quantity of the latter was then dissolved 

 in water, heated, and boracic acid added until all elBTervescence 

 ceased. To ascertain that equivalent proportions had been used, 

 ,the borax formed was crystallized ; the mother liquor withdrawn, 

 examined, and again crystallized 3 and this was carried on until the 

 whole had become borax. It was easy to ascertain with a very 

 minute drop of the mother liquor, whether carbonate of soda or 

 boracic acid were in excess : in the first case a little sulphuric 

 acid caused effervescence ; in the second, a little solution of soda 

 instantly caused a crystallization of borax. 



In this way 2.002 of dry subcarbonate of soda required 2.64 

 of dry boracic acid, and produced 7.185 of the ordinary crystals of 

 borax, which, according to the previous experiment, being equiva- 

 lent to 3.8116 of dry borax, gives 0,8304 for the carbonic acid 

 set free from the alkaline carbonate. 



Upon using some very pure crystallized boracic acid in place of 

 that which had been fuzed, it was found that the 2.002 of car- 

 bonate of soda required 4.660 to produce borax as before 3 from 

 which it may be concluded that the 4.66 contained 2.02 of water. 



From these results the following atomic compositions are 

 drawn, oxygen being 10. 



Pure boracic acid 1 atom 44 



Water ... 3 33.73 



Crystallized boracic acid 77.73 



Anliydrous Borax. Prismatic Borax, Octoedral Borax. 



Boracic Acid '. 2 atoms 88. 2 atoms 88. 2 atoms 68. 



Soda vii-n ^^i^ '4"^-^' . 39.09-^4^'^: 39.09 1 . 39.09 

 Water 'n'y^osi:-(. . ■ ^i6^^\ ll2A3 5 . 56.217 

 127.09 239.52 183.307 



Ann. de V Industrie, v. 156. 



16. On the Chloride of Lime, or Bleaching Powder, %M.Morin. — The 

 uncertainty of the sulphate of indigo, as a test liquor for chloride, 

 has been long known. M. Morin proposes to substitute for it a 

 solution of muriate of manganese. The same vessels as in Gay 

 Lussac's chlorometer may still be used, but a volume of this new 

 test liquor will represent 10 volumes of the old solution of indigo, 



