314 0)1 the Tinnwg of Copper , 



presented by M. Malouin to the Academy of Sciences at 

 Paris in 1741, in regard to the employment of zinc for tin- 

 ning iron and copper : the advantages he promised himself 

 were only illusory, and his expectations have not beerv con- 

 firmed by time. 



The second paragraph contains an account of a paper on 

 tinning, presented to the same academy by J. B. Kemerlin 

 in 1742. One may see there the examination of it by 

 Messrs. Hellot and Geoft'roy, who entertained an opinion 

 contrary to the assertions of the author. 



The same year the academy charged Hellot and Geoffroy 

 to examine the alloys of zinc proper for making vessels. 

 Ihe inconveniences pointed out by the two academicians, 

 as well as by many others, were verified by Proust ; and all 

 of them are inclined to proscribe such alloys. Having made 

 a mixture of equal parts of lead and zinc, similar to that 

 examined by the two commissioners, he obtained an alloy 

 of a pa>te-like consistence, as easy to be cut with a knife 

 as cheese, and difficult to be cast. M. Pierre Blanco, a 

 very ingenious pewterer, seconded the labours of Proust. 

 The first lime he poured the alloy into the mould, it did not 

 run sufficiently to fill it. He tried it a second time ; and, 

 when he thought he could draw it from the mould, it fell 

 into pieces, as they had no cohesion. Being desirous to 

 procure a piece well or ill moulded, he found himself obliged, 

 at the third time, to cool his mould in cold water, and to 

 employ double the time necessary to cast a piece of the 

 same size with common alloys : the vessel obtained broke 

 short, and was filled with defects which could not be re- 

 medied. A pound of alloy was employed, and the article 

 weighed onlv nine ounces. The whole of the residuum was 

 mere loss. The same article acquired in a month a dark 

 colour, and at the end of six months was covered with 

 oxide ; inconveniences which do not take place in vessels 

 of common tin. The author still continues to make se- 

 veral practical objections, to which no one has given an 

 answer. 



It is seen, therefore, that alloys of zinc are not so advan- 

 taii^eous as some have imagined ; and those who propose 

 them have n.-ither consulted chemistry nor practice. Before 

 thcv were presented to government for its sanction, it was 

 necessary to subject these alloys to the test of chemical 

 ao-ents : and this the author has not omitted. 



1st, A plate of the alloy in question being brought into 

 contact with vinegar, the latter contracted a vc ry disagreea- 

 ble metallic taste at the end of a day : on the third day, 



without 



