186 Miscellaneous Intelligence. 



Proportion in atoms. Observed density. 



3 tin, 1 lead 8.3914 



4 tin, 1 lead 8.1730 



5 tin, 1 lead 8.0279 



6 tin, 1 lead 7.9210 

 This table shews that tin a,nd lead dilate when mixed. This 



dilatation increases from the alloys, of 2. or 3 atoms of tin to 1 of 

 lead; and if there be a point where there is no dilatation, it must 

 be between these alloys ; in fact it is found toward the middle, as 

 the author ascertained directly. 



Amalgam of Tin. — The author has ascertained anew the den- 

 sity of mercury ; he has found it 13.5886, taking for unity that of 

 water at its maximum of density. At 26° of the centigrade scale, 

 it is 13.5350, and that of tin 7.2868. All the following experi- 

 ments have been referred to the same temperature of 26°. 



Proportion in atoms. Observed density. Calculated density. Ratio. 



3 tin, 1 mercury 8.8218 8.7635 1.006632 



2 tin, 1 mercury .9.3183 . 9.2658 1.005685 



1 tin, 1 mercury 10 3447 10.2946 1.004865 



1 tin, 2 mercury 11.3S16 . 11.3480 1.002960 



The following amalgams were made in the ratio of volumes, at 

 the temperature of 17 :— Density of tin, 7.2911; density of mer- 

 cury, 13.5569. 



Proportion in volumes. Observed density. 



1 tin, 1 mercury • 10 4729 



1 tin, 2 mercury 11.4646 



1 tin, 3 mercury 12.0257 

 These observations prove that tin and mercury in general under- 

 go a considerable contraction by amalgamating ; but this contrac- 

 tion is nothing when one volume of tin is alloyed with two volumes 

 of mercury, for the small differences between the results of observa- 

 tion and of calculation, which are seen in the above table, may be 

 disregarded. 



Amalgam of Lead. — The following experiments are referred to 

 the temperature of 17°. 



Proportion in volumes. Observed density. 



1 lead, 4 mercury 13.1581 



1 lead, 3 mercury 13.0397 



1 lead, 2 mercury 12.8648 

 It is here the amalgam composed of one volume of lead to three 

 of mercury, which undergoes the least contraction. 



Another curious result which it is easy to obtain from these ob- 

 servations is, that the dilatation of all these amalgams by heat is 

 less than that assigned by calculation, supposing that each metal 

 preserves its own dilatation ; it is therefore proved that the approxi- 

 mation of the molecules increases the resistance which their mutual 

 attraction opposes to the effect of heat. 



