144 On the Contraction which takes place in Mercury 



59*9 is the least diminution in the weight of mercury when 

 weighed in a solid state in alcohol, and that it is at this moment 

 when their spccific'iiraviliesare furthest from each other; for we 

 may observe that at ahiiost the next degree of temperature to 

 that ill which the mfrcury loses its fluidity, v;hilst the alcohol 

 preserves its fluid form, the mercury appears to become of 

 less specific gravity, as it loses 60; which gives, according 

 to calculation at L, only 11 ; but the fact appears to me to 

 be, that alcohol proceeds m the ratio of a fluid by decrease 

 of temperature, and that mercury, having obtained a solid 

 form, follows the ratio of contraction of a solid ; therefore 

 their densities approach each other. I should have ascribed 

 this greater loss of weight to the particles of the mercury at 

 •the moment of .crystallization occupying, in consequence of 

 their new arrangement, more space than at the moment be- 

 fore it became solid, as with some of the metals is known 

 to be the case, had I not carefully observed the passage of this 

 metal in other experiments, where I had an opportunity of 

 seeing the contraction proceed very distinctly; and had not the 

 mercury, also proceeding to still lower temperatures, lost 

 from €0, 60-1, 60-3, GOT, 60-8, and 6l, long after the 

 whole had becoire solid, and was suspended by the wire : 

 thus, 61 is the greatest diminution of weight by the abstrac- 

 tion of heat which I could obtain, and I am of opinion that the 

 space described by these changes of loss of weight demotes a. 

 rangeofmany degrees of temperature: how much greater the 

 density may then be than that stated at L, I cannot presume 

 to say ; but as it takes, with some probability, a proportion 

 of contraction approaching to that of silver, it certainly appears 

 improbable thai it should reach the specific gravityvvhich my 

 former calculation Irom a single observation led me to at- 

 tribute to it. I am therefore inclined to believe there was 

 some inaccuracy in weighing the silver by the hydrostatic 

 balance, when by my former cxjKTiments I gave S8'I, the 

 quantity of loss of ICOO gr. of silver: — from many observa- 

 tions in this laborious train of inquiry, it seems hardly possible 

 that the former could have been correct; for if the alcohol and 

 silvercontinuedto contract inthe samcproportionfrom56°be- 

 low zero,as they do from64"aboYe zero to that temperature, it 

 would appear that an abstraction of heat must necessarily have 



taken 



