TENACITY OF DUCTILB METALS. 103 



the author's experiments agreed with those of Dr. Thom- 

 son ; but with respect to other metals he differs from him. 



The examination of the tenacity of zinc appears the more Zinc deserving 

 to deserve attention, as it appears to be in contemplation, atteu lon " 

 to substitute it for lead in covering roofs of houses; and as, 

 ou account of its great dilatability, it was considered by 

 Smeaton particularly advantageous in the construction of 

 compensations for timepieces. , 



Mr. Morveau has examined it in different states : he tried Examined in 

 a bar of forged zinc purified by Mr. Vauquelin, sheet zinc ^ l ^ erent8tattS « 

 from Liiubourg given him by Mr. Descotils, and zinc la- 

 minated and drawn into wire by Messrs. Praire and Tournu. 

 The expression of the resistance, which was the mean term 

 of eight experiments, places it immediately after gold, as 

 in the following table. 



A wire of 2 rnillim. [0.787 of a line Eng.] Tab j e of tne 



in diameter of iron supported before it ... 1U . tenacity of dif« 



i . • u. * *'!; Ibs av0lr * ferent metals, 



broke a weight of 249*659 549*250 



Copper 137*399 302*278 



Platina 124*690 274*320 



Silver 85*06'2 187*137 



Gold 68*216 150*753 



Zinc 49790 109*540 



Tin 15*740 34*630 



Lead (calculating by the dimensions at 



the point of rupture) 12*555 27*621 



(calculating by the dimensions be- 

 fore it stretched) 5*623 12*371 



The author would have included nickel in this table, now Nickel, 

 admitted into the class of ductile metals, and the tenacity 

 Of which Mr. Kichter presumes must be very considerable; 

 but the trials to which he subjected it gave only a tenacity 

 of 47*67 kil. [104*875 lbs.] for a wire of the above diame- 

 ter. It is true the piece he tried, which he had from Mr. 

 Vauquelin, and which he considered as pure, did not exhi- 

 bit in the process of flatting all the ductility, that Mr. 

 Hichter announced; whence he inferred, that we must wait 

 for more decisive experiments, before its place 10 the tabie 

 can be absolutely determined. 



Two 



