78 Intelligence and Miscellaneous Articles. 



tained, which at first deposits crystals of paratungstate of ammonia 

 (common bitungstate) ; the mother-water, evaporated and treated 

 httle by little with hydrochloric acid, becomes a thick mass of very 

 fine needles united in spheres ; these contain tungstic acid, ammonia, 

 peroxide of iron, peroxide of manganese and water; but no reagent 

 indicates the presence of tungstic acid or of the peroxides of iron and 

 manganese. 



By ebullition with acids or alkalies, this ferri-mangani-tungstate is 

 decomposed, and then the presence of the acid, and of iron and man- 

 ganese is readily ascertained. It is also decomposed by drying at 

 392°, and it then redissolves readily in water ; but, by evaporaton, 

 it gives a mixture of hexagonal tables of a deep rose-red colour, and 

 of white or slightly yellowish needles. 



With bichloride of platina, a precipitate of chloroplatinate of am- 

 monia is obtained, and the solution, evaporated^to the consistence of 

 a syrup, gives ferri-mangani-tungstic acid. 



The ammoniacal salt appears to consist of — 



W5 0'' f ^ Mn^ Am^ H^ + 9 Aq. 

 There certainly exists another ferritungstic type, for as already 

 stated, wolfram, treated with nitre and carbonate of potash, gave a 

 gummy salt. As this may be heated to ebullition with carbonate of 

 potash without depositing peroxide of iron, it must belong to a dif- 

 ferent type from that to which it gives rise, by the influence of acids. 

 Comptes Rendus, Novembre IS, 1850. 



ON DULCOSE. BY M. A. LAURENT. 



The author states, that some months since he presented to the 

 Academy a memoir on a new kind of sugar, to which he gave the 

 name of dulcose, and to which he gave the formula C" H"** 0'^-|-3Aq, 

 which makes it an homologue of glucose. At the last sitting of the 

 Academy, M. Jacquelain communicated a memoir on the same sub- 

 ject, and gave to dulcose the formula C" H'^ O'". 



M. Jacquelain having inadvertently compared his results with M. 

 Laurent's calculation of dulcose, supposed to be anhydrous, and having 

 thereby found differences which were too great, sent to M. Laurent a 

 very pure specimen of dulcose, requesting him to repeat the analysis. 



The following are the results of M. Laurent's fresh analysis, com- 

 pared with that of M. Jacquelain, and the theoretic results of both : 

 Lanrent. Jacquelain. 



lUO 100 



The analyses of M. Jacquelain, it is remarked by M. Laurent, agree 



perfectly with the formula proposed by him, or C''* H'^* 0'*-|-2 Aq. 

 If M. Jacquelain's formula were correct, it must be admitted that 



in the 10 analyses which were made, 2 to 3 thousandths less of 



hydrogen were obtained than by calculation, which is contrary to 



what happens in all analyses. 



