354 
DR. DALTON ON THE CONSTITUTION OF THE ATMOSPHERE. 
Quadrisulphuret of Lime, in the humid way. 
When sulphur and hydrate of lime in almost any proportions are boiled together 
in water, quadrisulphuret of lime is formed and dissolved in the water ; the solution 
is of a deep yellow colour, and has a very bitter taste. I have not seen in any author 
the proportion that ought to be used, nor the quantity and specific gravity of the 
liquid solutions. These are subjects which have engaged my attention. If lime is 
in excess, the liquid consists of lime water holding in solution quadrisulphuret of lime. 
If sulphur is in excess, the liquid consists of water holding in solution quadrisulphuret 
of lime. I have long known that the economical proportions to be used are 32 parts 
of dry hydrate of lime by weight with 56 of sulphur, that is, one atom of lime with 
four atoms of sulphur. If more lime than that above be used, it will be found pre- 
valent in the residue ; if more sulphur, then the redundant sulphur will be found in 
the residue. A few ounces of the mixed ingredients may be gently boiled in an iron 
pan for an hour or more, stirring the liquor occasionally, and covering the pan with 
a lid to prevent the too free admission of atmospheric air. Or, in order to prevent 
the action of oxygen on the liquid, a flask may be substituted for the pan ; the ma- 
terials may be put into the flask nearly filled with water, and the flask loosely corked 
may be immersed in a pan of boiling water so as to be almost covered by the water. 
The liquor to be preserved should be kept in green glass bottles nearly full, and having 
ground stoppers. After the boiled liquor has cooled and the sediment subsided, the 
clear liquor may be decanted ; if it be strong or deep coloured the sediment may be 
washed with a little water, and another quantity of the liquor obtained of inferior 
strength. The sediment may be dried if necessary, and subjected to analysis, as I 
have mostly done. The quantity and specific gravity of the clear liquors should then 
be ascertained. 
The first quadrisulphuret of lime I made was in 1804 ; it was very weak, since it 
only absorbed one fourth of its bulk of oxygen gas ; the next that was made took its 
bulk of oxygen. The next, made in 1806, took times its bulk of oxygen. In these 
no account was taken of quantities or residues of lime and sulphur. After this I saw 
the necessity of investigating, (1.) the quantities of lime and sulphur mixed ; (2.) the 
quantity and specific gravity of the liquid obtained ; and (3.) the quantity and pro- 
portion of the materials left in the residue, in order that the rationale of the changes 
effected might be explained. From 1806 to the present time (1837) I have made no 
quadrisulphuret of lime without attending to all those particulars. In this period I 
have made it 23 times, six of which were in flasks, and the rest in iron pans covered 
as mentioned above ; the difference of the two methods I found to be very little ; it 
consisted chiefly in traces of sulphuret of iron being found in the residues when pans 
were used. 
A few trials of the various liquids obtained soon furnished me with a formula for 
ascertaining the quantities of sulphur and lime in a liquid of given specific gravity ; 
