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The salts which we have hitherto examined have been those 

 ^ftltible in water, and having a constitution to a certain degree 

 well-defined. We have now to consider the insoluble sub- 

 salts, and, in some cases, their neutral insoluble types, and 

 also to ascertain how far the results thus obtained serve to 

 throw light on the constitution of ammoniacal salts. 

 . ■'^^Subsulphate of Copper, CuO, SO3, 4HO + 3CuO = 234-9. 

 —This well-known salt was made by adding ammonia to a 

 "{^lution of sulphate of copper. The fourth part of an equi- 

 valent, 58*7 grains, thrown into water, caused an increase of 

 19*1 aiid' 19'Q itt two Successive experiments; " "' ' 



I. Subsulphate of copper, vol. of salt 76'4 ... 3'074 

 II. ... ... 76-0 ... 3-090 



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j^Subsutphate of Zinc, ZnO, SO3, 3ZnO, 4H0 = 237*3.— 



This salt is apt to combine with more water than four atoms, 

 but may be obtained with four by drying at 212°. On placing 

 29-66 grains, the eighth part of an equivalent, in turpentine, 

 an increase of 9*5 was obtained : and on treating 22-8 in a 

 similar manner, the rise in the stem was 7*3. Both of these 

 experiments exactly agree in making — 



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Odv'i^' Subsulphate of zinc, vol. of salt 76-0 .... 3*122 .11 



y^ Sulphate of Protoxide of Mercury, HggO, SO3 = 251*0.-^ 

 This salt was prepared in the usual way by digesting one part 

 of mercury in 1 ^ part of sulphuric acid. The fourth of an 

 equivalent, 62*75 grains, thrown into turpentine, increased 



^^r''''tt|,dffe5^iiofsalt 33-2 ... 7^6d'^'''' '''^'^ 



> ! ' Sulphate of Peroxide of Mercury, HgO, SO3 = 149*6. — 

 The salt used in the experiment was prepared by heating five 

 parts of sulphuric acid mixed with a little nitric acid, with four 

 parts of mercury until the whole became a dry saline mass. 

 On immersing 37*5 grains of the salt thus prepared in tur- 

 pentine, an increase of 5*8 was obtained, which gives 23*1 for 

 the volume of the equivalent, and 6*466 for the specific gra- 

 vity of the salt. 



!,iU Subsulphate of Mercury, HgO, SOg -f 2HgO =368-46.— 

 •The last salt thrown into water and washed with warm water 

 is converted into the beautiful yellow powder known as tur- 



