PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 541 



electrical agency; and it is certainly a very easy mode of disposing of a 

 subject. But what is electricity ? I remember being present a few years 

 since, when a young man, not a student of chemistry, however, asked Dr. 

 Charles T. Jackson what catalysis meant. He replied that it really meant 

 " what God knows but man does not." The word electricity is quite popu- 

 larly employed in this sense. 



My reflections led me, as I have said before, to attach much importance 

 to thermo-electricity, as heat cannot be converted into electricity and elec- 

 tricity into heat. And the time may not be far distant when this mode will 

 be -employed to light our factories, and even perform labor. Eventually 

 electricity may be made to complete a circuit of clianges like water, which, 

 after turning the mill wheel, evaporates into the clouds and again descends 

 in rain, thus swelling the stream and doing the same work over again. 



The lateness of the hour prevented any further discussion of this sub- 

 ject, and it was therefore continued for the next meeting. 



Adjourned. 



American Institute Polytechnic Association, ) 

 December 31st, 1863. j 



Chairman, S. D. Tillman, Esq.; Secretary, Mr. B. Garvey. 



Mr. J. K. Fisher exhibited a drawing of his plan for a steam omnibus. 



The Action of Water upon Lead Pipe. 



Prof. Everett, chairman of the committee on the use of lead pipe for con- 

 veying water, and tin-lined lead pipe, made the following report, which 

 was accepted: 



6 Lead Pipe. 



Your Committee have thought it expedient, before entering in details np- 

 OTi the subject before us, viz. : "The action of water upon lead pipe," to 

 give a short account of the chemistry of both lead and tin, to be followed 

 by a brief comparison of these interesting metals. 



Lead has been known from the earliest times, and even among uncivilized 

 nations it has been in use, probably from the ease with which it is re- 

 duced to the metallic state from the ore which contains it, for lead is sel- 

 dom, if ever, found in nature in the form of metal, but most generally in 

 combination with sulphur forming a sulphuret of lead or galena, which, 

 when pure, contains 86.66 per cent, of lead, color, bluish gray, with a high 

 lustre when freshly cut, but which, when exposed to the action of air, soon 

 disappears by the formation of a slight coating of sub-oxide, which is the 

 cause of the usual dull appearance of lead ; it melts at about 612©, and has 

 a specific gravity of 11.33 or nearly twelve times the weight of an equal 

 volume of water. 



A knowledge of the action of the most common of the mineral acids up- 

 en lead, is important to enable the investigator to form an intelligent 

 opinion upon the question before us, and equally important in its bearings 

 on the test of the detection of lead when in solution, which, fortunately 

 are very delicate, and can be used with the most convincing effect, by any 

 one interested enough in the subject to employ the means herewith des- 

 cribed under the head of 



