and on the Sulphur ets of Lime, 167 



of inferior strength. The sediment may be dried if necessary, 

 and subjected to analysis, as I have mostly done. The quan- 

 tity 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 oxy- 

 gen. The next, made in 1806, took 2^ times its bulk of 

 oxygen. In these no account was taken of quantities or re- 

 sidues 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 proportion 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 ; namely, mul- 

 tiply the three leading decimals in the specific gravity of the 

 liquid by 1 3, and the product will give the aggregate weight 

 in grains of sulphur and lime in 1000 water grain measures 

 of the liquid; of this aggregate y^^th will be sulphur, and j^^th 

 lime. 



With regard to the residue after boiling and its analysis, it 

 is obvious the residue must consist chiefly of sulphur and lime, 

 which for want of due continuance of the ebullition have 

 escaped combination ; and there may be some impurities in 

 the sulphur, or the hydrate of lime may not be free from car- 

 bonate, &c. ; but when the residue is comparatively small no 

 material disturbance of proportions in the quadrisulphuret 

 car^ take place. If the residue be chiefly sulphur, its quantity 

 may be approximated by ignition ; but if lime is in excess, it 

 may be estimated by the quantity of muriatic acid required 

 to saturate it. 



The following table exhibits a selection of the principal 

 varieties in the proportions of ingredients and products ob- 

 tained so as to illustrate the foregoing statements. 



