On the EfeB of a MUture of Tin with Getd. 



ir^ 



!y 32,5 inches above the centre of the orifice. The times of emiffion were as in the fol- 



lowing table. 



I tnuft here obferve, that the vifcidity or mutual adhefion of the particles of the water * i$ 

 of very little confequence to the increafc of expenditui-e through the orifice B O, fig- 7, by 

 the additional tube B C. For as foon as a fmall hole is opened at K the increafe of expendi- 

 ture diminifties or entirely ceafes, and the fluid is no longer continuous in the tube. 



We will now return to tubes in the horizontal and afcending fituations. 



{_ To bi continued. ] 



viir. 



Experiments and Obfervations on the EffeEl of Annealing a Plate of Metal, conftjling of fine w 

 alloyed Gold, with one twenty-fourth Part of Tin. By MATTHEW TiLLET. 



[ Concluded from page i4z. ] 



I 



HESITATED to ufe my gold of 24 carats, from the juft fear I had that it would 

 lofe the advantage of being the duflile of metals, and that I could not reftore this property 

 but by the method of parting. For this reafon I determined to begin my experiments on a 

 more decifive fcale than the former, upon gold of 22 carats, or alloyed with -r-'^th part of 

 copper. In this manner I fhould repeat fome of the experiments related by Mr. Alchorne, 

 from which he has conftantly inferred that tin, mixed in a certain proportion with gold of 

 this fame finenefs of 22 carats, does not deprive it of its dudlility. 



I therefore alloyed i gros 24 grains of tin taken from the ingot deprived of arfenic, 

 which I have mentioned, with 4 ounces of gold, the finenefs of which, namely 22 carats, 

 was perfeftly well afcertained. Thefe two metals, reduced into fmall pieces, were mixed 

 together, put into a crucible, and urged by the ftrong heat of a forge with two pair of bel- 

 lows. When their fufion appeared to be complete, I poured the metal into a fmall ingot- 

 mould proportioned to the quantity. 



The ingot thus obtained had loft fcarcely any thing of the weight of the two metals that 



compofed it, which was a proof that the tin had united and incorporated with the four 



^ ounces of gold. But on attempting to bend the ingot, which was about fix inches long 



and not more than two or three lines thick, I remarked, contrary to the nature of gold of 21 



carats, that it was rigid, and would have required a confiderable effort to give it any degree 



• Gravefande and others have attributed the increafe of expenditure through defcending tubes, to the natural 

 cohffion of the particles of water. V. 



A a a of 



