50 



E. DIVERS AND T. HAGA. 



timation of hydroxylamine and sulphuric acid by hydrolysing in 

 sealed tubes with dilute hydrochloric acid kept for some time 

 at 100° and only then heated t(j 180°. Some of the attempts to 

 estimate hydroxylamine wei-e however defective for the reason already 

 given (p. 4:2). The sodium was directly estimated by cautious 

 io-nition with sulphuric acid, the presence of which prevents explosive 

 decomposition of the salt by heat. 



Disodiuiii .^alt. Na.HNSoOy. — This salt is anhydrous and is soluble 

 in somewhat more than its own weight of water nt 14°. It just red- 

 dens litmus. Its crystals are usually small, dense, brilliant prisms, 

 united into hard masses and tii-mly adhering to the glass. On 

 analysis it has given : — 



Calc. Found. 



Sodimn 19-41 19-21 19-5Ö 



Sulphur 27-00 1^7-06 26*98 



Fjight-ninths noniuil .sudiiuii sali, Na.HNSoO;, 2Na3NS207, 3H..0. — 

 The solutions inlcruiediate in composition to those of the trisodium 

 and disodium salts which yield this when evaporated may be pre- 

 pared by adding either sodium hydroxide or ti'isodium sab to a 

 solution of disodium salt in approximately the calculated quantit}^ 

 Twice, when the solutions were left in the desiccator to evaporate and 

 were of the composition of the unknown five-sixths normal salt, good 

 sized prisms and plates of some salt filled the solution which when 

 the attempt to remove them was made, i'a[)idly melted away very 

 remarkably, to give place to a precipitate of the eight-ninths sodium 

 salt. Possibly, they were crystals of tlie five-sixths salt. The eight- 

 ninths salt, redissolved in water or in its diluted mother-liquor, gives 

 on evaporation small nodules of the salt. Only under the microscope 

 can this precipitate and these nodules be made out to be composed of 

 prismatic crystals. The crystals are eftlorescent. Like the other 



