14 
second, an apparent slight drop in the thiosulphate figure, for which 
no explanation is offered, since the phenomenon appeared too quan- 
titatively insignificant to warrant special investigation. Both 
changes, in fact, are so slight as to be entirely negligible for practical 
purposes and under ordinary conditions. 
For the actual preparation of lime-sulphur solutions equations 1, 
2, and 3 call for the use of 13.7 parts of available calcium oxid 
to 100 parts sulphur. That the laboratory experiments did not pre- 
cisely check this theoretical ratio is attributable solely to the decom- 
positions represented by equations 5 and 6. The decomposition 
represented by equation 5 is independent of the formula employed 
and in no way changes the relative proportions of primary in- 
gredients called for; that is, equation 5, following the postulated 
escape of hydrogen sulphid, produces neither free lime nor free 
sulphur, and leaves the solution neutral. There remains then only 
the matter of oxidation to be considered. But that is a surface action 
solely, and considering the enormous advantage in the ratio of vol- 
ume to surface possessed by even moderate-sized cooking vats over 
laboratory apparatus, it approaches a negligible factor. Therefore 
the theoretical ratio becomes the actual ratio which should be fol- 
lowed in practice, provided only the concentration is not sufficient to 
allow equation 7 to progress from left to right. The formation of 
sulphite becomes a significant factor when the formula employs some- 
what more than 20 parts of sulphur per 100 volumes of finished 
solution. For a number of reasons the writer believes that it will 
be generally inadvisable to try for a much higher degree of con- 
centration in " homemade " solutions. Certainly in such solutions 
no allowance should be made for the formation of sulphite by in- 
creasing the ratio of lime to sulphur, as the extent of the decomposi- 
tion is too dependent on the degree of concentration and length of 
boiling after the solution is otherwise complete. Attempts to make 
more concentrated solutions are attended by greater difficulty in 
manipulating the thick liquid and in avoiding loss by boiling over, 
and moreover involve more loss of the finished solution in the 
wet sludge, especially since the volume of sludge is increased by 
deposition of calcium sulphite. 
Nowhere is there evidence of the existence in cold solutions of more 
sulphur, either free or combined, than corresponds to the formula 
CaS 5 . On the other hand, a properly prepared homemade solution 
will contain at most but a small amount of tetrasulphid. It will also 
contain a very small amount of hydrogen sulphid. some of which 
may possibly be in the form of calcium hydrosulphid. While rigidly 
scientific proof that the two apparently definite proportions of, re- 
spectively, four atoms and five atoms of sulphur to one atom of cal- 
cium may not, in fact, arise from mixtures of lower and higher 
