IMEECUEIC, STANNIC, AND PLUMBIC ETHYLS. 
431 
of tlie alloy very slow, even when brought to the boiling-point of iodide of ethyl. 
Neither bromide nor iodide of ethyl showed any tendency to combine with granulated 
lead when exposed to a clear April sun for one week, neither did the bodies unite 
under pressure and a temperature of 170° C. The bromide in the last case was quite 
unchanged ; but the iodide gave crystalline plates of iodide of lead and gaseous matter. 
Action of Zincethyl on Chloride of Lead. 
Chloride of lead turns black immediately it comes in contact with zincethyl. It sinks 
in the liquid, and forms a crust which is so hard that it will be found more convenient 
to operate in a bottle than in a retort. In the former vessel the chloride may be incorpo- 
rated with the zincethyl without fear of fracture. 
As soon as the chloride of lead ceases to change colour, the vessel is placed in a water- 
bath and heated to 100° C., after which the liquid, when cold, may be decanted. This 
liquid fumes slightly in the air from the presence of zincethyl, which cannot be wholly 
saturated even when much chloride of lead is*in excess, A compound of the lead 
radical and zincethyl is thus obtained, which may be treated with very dilute hydro- 
chloric acid and then washed with water. The mass of chloride of zinc in the first 
bottle may be made to furnish an additional quantity of the radical, by agitation with 
anhydrous ether. 
Considerable difficulty was experienced in freeing this radical entirely from ether. 
When distilled, the thermometer rises rapidly to nearly 204°, at about which point the 
vapour suddenly decomposes with a slight explosion and deposit of metallic lead. 
This difficulty was overcome by conducting the distillation under reduced atmospheric 
pressure, in a simple condenser a sketch of which is annexed. (See p. 433.) 
The apparatus was found very conveniently to permit of frequent change of the receiver, 
without disturbing the tightness of the various joints.' When the barometer stood at 
30 ’S inches, the radical passed over without the least decomposition at a temperature of 
162° C., under a pressure of about 7 '5 inches of mercury, thus depressing the boiling- 
point in a remarkable degree. 
In filling the bulbs for combustion, the precaution was taken of employing the air- 
pump ; and before proceeding to burn the substance, it was found necessary again to 
empty the bulbs by exhaustion. 
I. 0‘3615 grm. of substance gave 0’3928 grm. carbonic acid and 0‘2000 grm. water. 
II. 0*3116 grm. of substance gave 0*3400 grm. carbonic acid and 0*1775 grm. water. 
The composition in 100 parts accordingly is — 
I. II. 
Carbon ..... 29*62 29*74 
Hydrogen .... 6*14 6*32 
the formula, 
PbC^H.o, or Pb(C, Rf 
3 L 2 
