312 



PROCEEDINGS OF THE AMERICAN ACADEMY 



Calculated for (C 7 H 6 ClS0 3 ).,Pb. H 2 0. 

 Water 2.83 



Lead 32.55 



Found. 

 5.00 2.93 



32.43 



0.1742 gr. of the salt dried at 100° gave 0.0850 gr. of PbS0 4 . 



Calculated for (C 7 H 6 ClS0 3 ).,Pb. 

 Lead 33.50 



Found. 

 33.34 



It crystallizes in long white needles grouped in sheaves or stars, 

 which are not freely soluble in water. 



Two Basic Lead Salts were obtained by treating the mother-liquor 

 from the preceding salt with an excess of plumbic hydrate; one crys- 

 tallized from water by spontaneous evaporation in little spheres made 

 up of radiating needles, and seemed to be free from water of crystal- 

 lization, although it blackened and lost weight at 160°. 



0.3384 gr. of the salt dried at 1 00° gave, after precipitation with 

 dilute H 2 S0 4 , 0.2890 gr. of PbS0 4 . 



Calculated for (C.H 6 ClS0 3 ;oPb 8 0. 2 . 

 Lead 58.35 



Found. 

 58.34 



The formula of this salt is therefore (C 6 H 4 ClCH 2 S0 3 ) 2 Pb s 2 . 

 The second salt which crystallized from a hot concentrated solution 

 in white scales had the formula C 6 H 4 ClCH 2 S0 8 PbOH . H O. 



0.2128 gr. of the salt dried in vacuo lost at 120° 0.0087 gr. 

 0.2747 gr. of the salt dried in vacuo gave with dilute H,SO 

 0.1870 gr. PbS0 4 . 



Calculated for C 7 H 6 ClS0 3 PbOH . H 2 0. Found. 



Water 4.02 4.08 



Lead 46.26 46.49 



To obtain the Free Acid the lead salt, which had been purified with 

 great care, was suspended in water, and decomposed with sulphuretted 

 hydrogen, the filtrate from the plumbic sulphide formed was evapo- 

 rated in a stream of sulphuretted hydrogen, first on the water-bath, 

 and finally at a still lower temperature, until it had attained the con- 

 sistency of syrup ; it was then put in vacuo, where after standing 

 some time it crystallized in square plates, which, however, soon 

 turned yellow, while fumes were given off which smelt of hydro- 

 chloric acid and benzaldehyd. These yellow crystals melted at 108°, 

 but the evidences of decomposition were so marked that we do not 

 consider this the true melting-point of the acid, nor did it seem worth 



