32 REVIEWS — CANADA AT THE UNIVERSAL EXHIBITION. 



PINK SALT. 



V. 1.0575 grms. gave 0.418 Mn s O* =36.77 per cent. MnO 

 1.3700 " " 0.536 " = 36.79 " " 



VI. 1.4395 " u 0.567 " = 36.64 « " 

 1.5300 " " 0.597 " = 36,39 " " 



Mean 36.62. 

 1.5300 heated to 212°.F. lost 0.134 HO = 8.75 per cent. HO, 

 and became perfectly white. 



The formula MnO, C 2 O s +3 HO requires 36.09 per cent. MnO 

 and one equivalent of water would = 9.09 per cent. 



The red oxide of manganese is obtained by heating this salt, in a 

 crystalline form ; the complete conversion of the protoxide into the 

 red oxide is only effected after a rather long roasting, 



Burin du Buisson is of opinion that pure salts of the protoxide of 

 manganese are colourless when in an anhydrous state, but reddish 

 when hydrated, while Reithner and others ascribe the red colour to 

 the presence of a salt of the sesquioxide. The pink colour of the 

 above hydrate can scarcely be owing to the latter cause, inasmuch as 

 the salt is produced both by oxalic acid and by oxalate of potash ; 

 and the salt with 2 HO is generally obtained perfectly white. (This 

 salt is described by Liebig as having a tinge of pink, but in my ex- 

 periments it was always white.) The pink crystallized salt changes 

 in a warm atmosphere, even when kept in a close vessel, into the 

 white compound, evolving ^ater. 



The oxalate dissolves readily in a hot solution of oxalate of ammo- 

 nia, and crystalline compounds can be obtained as already described 

 by Winkelblech : these crystalline crusts, however, seem to vary much 

 in their composition, and are probably combinations of the true 

 double salt with variable proportions of oxalate of ammonia, similar 

 to the magnesia compounds lately described by Souchay and 

 Leussen. 



REVIEWS. 



Canada at the Universal Exhibition of 1855. — Printed by order of 

 the Legislative Assembly. Toronto : John Lovell, 1856. 

 The success which attended the Canadian exhibition at London, in 

 1851, naturally led to the expectation that no efforts would be spared to 

 present at Paris, in ]855, a correct representation of the Natural Pro- 

 ductions and Industry of this vast Province. 



