AMERICAN INSTITUTE. 549' 



aMe to manufacture chain cables of greater tensile strength than any here- 

 tofore made. Jones & Co., were about to abandon the manufacture of iron 

 pipes until they began to use franklinite in the proportion of from five to 

 twenty per cent, when their tubes were found to be of such excellent qual- 

 ity that they got as much work from the city (New York) as they could 

 do. And afterwards the city of Albany took all the water pipes they could 

 supply, Washburn & Co, have drawn wire as fine as No. 32 from the pud- 

 dled bar direct. 



The subject for next Thursday's discussion will be " Aluminium" and 

 ♦'Zinc," 



Polytechnic Association of American Institute, ) 



January 19?A, 1800. \ 



Prof, Mason, chairman, John Johnson, Esq., secretary pro tern. 



During the half hour devoted to miscellaneous business, Mr. Montgo- 

 mer}' exhibited a specimen of his cast iron pavement, which was deemed a 

 coflvsiderable improvement upon the kinds in common use. It consists of 

 undulating ribs formed upon plates of cast iron, ia such a manner as to 

 aiford a "hold" or "grip" for horses feet, both in the line of traction 

 and in a lateral direction, to prevent slipping. 



Mr. J. W. Worthen brought before the club his method of calculating 

 interest and making averages. He gave no explanation of his method, 

 and seemed resolved to be mysterious. 



Mr. Wykoff explained his method of saving the minute particles of gold 

 which are found floating in the water employed in gold washing. His 

 method is to place mercury in a trough over a fire, the trough being filled, 

 over the mercury, with wa4;er. The vapor of the mercury, rising through 

 the water, meets and amalgamates the small specks of gold, and the amal- 

 gam settles down again, the mercury being condensed by the cold of the 

 water which in an open vessel can never l?ecome hotter than 212 deg. 



Professor Mason, the chairman, introduced the subject of the evening, 

 by reading the following paper on 



ZINC. 



In a remote age the metals known to man had reached the sacred number 

 seven. Grold, silver, copper, mercury, tin, lead and iron, equaled the 

 seven days of creation, the seven stars, the seven colors of the rainbow, 

 'the seven sounds of music, the seven sons of Job, and the seven wise men 

 of Greece. To have searched for more would have been presumption in a 

 philosopher, and impiety in a priest. 



But nature thrust upon the notice of lead miners an eighth sabstance, 

 which had a faint metallic lustre, and was fusible at a lovf point, but was 

 extremely brittle and intractable, and the miners rejected it as "blind 

 lead." But nature (regardless of popular opinion) thrust this same mate- 

 rial on the attention of metallurgists, in combination with carbon and 

 silica, until the alchymists resolved to examine it. 



