9 
(6.) 100 cc. CaS0 4 solution mixed with 50 cc. NaCl solution 
= 1166*5 mgms. NaCl. 
Amount of CaS0 4 in solution after 28 days = 103*0 mgrms. 
Hence amount of Na 2 S0 4 produced = 93*9 mgrms. 
(c.) 100 cc. CaS0 4 solution mixed with 100 cc. NaCl solution 
= 2333 mgrms. NaCl. 
Amount of CaS0 4 in solution after 28 days = 64*0 mgrms. 
Hence amount of Na 2 S0 4 produced = 132*7 mgrms. 
3. It is very evident then that Graham’s supposition is 
correct. Without the aid rendered by diffusion time alone 
is sufficient to bring about a decomposition of calcium sul- 
phate in solution by sodium chloride, also in solution. If 
this decomposition is then realised in the Laboratory, there 
can be little doubt that under the more favourable condi- 
tions offered by the soil, the decomposition will play a 
somewhat important part in the nutrition of plant life. 
4. The numbers which I have obtained show that the 
extent of the decomposition under consideration is influ- 
enced not only by the time during which the salts are 
allowed to remain in contact, but also by the mass of 
sodium chloride employed. The amount of chemical action 
is almost directly proportional to the mass of the sodium 
chloride employed, the amount of calcium sulphate remain- 
ing constant. 
“On some Thionates,” by H. Baker, Student in the Owens 
College. Communicated by Professor C. Schorlemmer, 
F.R.S. 
Having been lately working on these salts, I offer the 
following observations : — 
Barium Dithionate. BaS 2 0 6 2Aq. According to Heeren* 
this salt is soluble in IT parts of boiling water; but he 
does not give the boiling point of the saturated solution; 
this I have observed to be 102°, and its solubility at this 
*Pogg. Ann. 7, 172. 
