660 TRANSACTIONS OF THE 



There are two ways of getting sulphur away from the ores of lead. 1st. 

 By using some substance having a greater aiEnity for sulphur than lead 

 has — iron for instance. 2d. By roasting the ore containing the sulphur, 

 in contact with oxygen. In this process sulphuric acid is first formed, but 

 by increasing the heat, the sulphur takes up two more equivalents of oxy- 

 gen and sulphurous acid is the result. The roasting process is employed 

 out west. 



The English crush the ore and roast it in a reverberatory furnace, the 

 beat being applied cautiously for a certain time, and the metallic lead 

 being allowed to flow from the bottom of the furnace. The lead for the 

 use of the whole world is produced in Europe and this country, a little 

 being also produced in Mexico. Whatever silver is produced in England 

 ii obtained from the lead ores. America and Mexico are the only countries 

 of the world which produce a silver ore. 



Mr. Fisher asked for information on the poisons from lead water pipes. 



Dr. Weatherby said that the poison proceeded from carbonic acid in the 

 water, which uniting with the lead gave the characteristic effects of lead 

 poison. In a recent number of the " Medical Journal" the idea of poison 

 from lead pipes was shown to be erroneous. A certain amount of heat is 

 necessary to form a soluble compound of lead ; oxygen or carbonic acid 

 escaping from the water in summer may combine with the lead, giving the 

 oxyd or the carbonate, which are considered poisonous. 



Mr. Seeley. — No doubt lead is a poison as well as arsenic. Persons' 

 constitutions differ as regards poisons. So some painters have colic while 

 others use lead with impunity. The same is the case with arsenic ; the 

 dog may not be affected by it, while the cat is. Poisons in general, how- 

 ever, act upon animals and plants. In a recent case in England, the ani- 

 mals and plants near a factory were acted upon by the poisonous fumes 

 coming from the same. The metallic lead is not dangerous, but the oxyd 

 is. Essential oils must be oxydized to yield an odor to have an effect upon 

 the human frame. Lead volatilizes to some extent ; hence long flues are 

 used to collect the condensed vapor. There is a popular error that -pure 

 water will not act on lead. The purer the water the more likely to dis- 

 solve the lead. The Croton is pure enough to dissolve lead. Chlorine in 

 water will form the poisonous chloride. The carbonates are not poison- 

 ous. Lead itself will not dissolve in water ; no metal will ; what we call 

 a copper taste in water is not produced by solution of copper ; it is a 

 minute portion of oxyd. When carbonate of lead forms on the inside of 

 the pipe, it protects the lead from oxydation. 



Dr. Young explained that the action of lead was not inflammatory. It 

 tended to produce palsy. 



Mr. Geisenhainer wished to know if lead wire and lead straps were inju- 

 rious to plants. The answer was in the negative. 



Major Serrell mentioned that the U. S. expedition to the head waters of 

 the Mississippi had discovered a vein of lead on their return from the 

 Columbia river, and while still to the west of the Mississippi. This vein 



