Chemical Science, 467 



9. On a peculiar Nitric Acid, and Sulphate of Potashy by Mr. 

 Phillips. — For the purpose of preparin<r nitric acid of the greatest 

 Etrenfrth, Mr. Phillips mixed 70 parts of nitre with 70 parts of oil 

 of vitriol. S. G. 1.8442 at 60^ and distilled for eight hours. The 

 nitric acid obtained was reddish yellow, weighed 46.13 parts, was 

 of S. O. 1.5033, and by an experiment on carbonate of lime, was 

 found equivalent to 34.24 of that substance ; the latter fact indi- 

 cates that 36.98 of real acid was present, and the liquid acid there- 

 fore consisted of 



Real nitric acid. , . . , 36.98 or 80.16 



Water 9.15 .. 19.84 



46.13 100.00 

 Supposing" this acid to be a definite compound of two atoms of 

 acid, 108, and three of water 27, it would consist of 



Real acid 36.90 or 80 



Water 9.23 .. 20 



46.13 100 



The salt remaining in the retort weighed 92.87 parts ; nearly this 

 weight of water being added and heated, the whole was dissolved, 

 and on cooling, a salt, consisting of extremely minute filaments 

 resembling asbestos, was obtained, which, by capillary attraction^ 

 retained a part of the residual solution so powerfully, that it was 

 necessary to absorb it by filtering paper. 



Although it appeared improbable that the crystals could be a 

 variety of the known form of bisulphate of potash, yet supposing it 

 might be that salt with either less, or more than two atoms of water, 

 Mr. Phillips proceeded to its analysis. Some of the salt was readily 

 dried by exposure to the air of a warm room: 100 grains, by mu- 

 riate of baryta gave 154.75 grains of sulphate of baryta, equivalent 

 to 52.45 sulphuric acid ; 109 grains heated to redness, lost 21.6 sul- 

 phuric acid and water, and left 78.4 grains of neutral sulphate of 

 potash. The latter contain 35.6 grains of sulphuric acid, which, 

 subtracted from the whole quantity of 52.45, indicates 16.85 as 

 the quantity dissipated by heat ; and this again, subtracted from the 

 21.6, indicates 4.75 water in the crystals. The quantity of acid 

 separated by heat is, therefore, very nearly half that remaining in the 

 neutral sulphate, and the salt in question appears to be a sesqui- 

 sulphate of potash, consisting of 



theory. experiment. 



3 atoms sulphuric acid 120 55.33 52.45 



2 „ potash 96 42.66 42.80 



1 atom water 9 . . . . 4.00 .... 4.75 



225 99.99 100.00 



Mr. Phillips found it difficult to prepare the sesquisulphate free 



