83 



BEPORT 1873. 



included, is quadratic. The way in which the octahedron and dioctahedron are 

 balanced in Leucite is an exceptional fact in mineralogy. The streaks seen on 

 Leucite under the microscope by polarized light are now explained; they are 

 twin plates. And the double relraction of Leucite is explained. It is not ne- 

 cessary to have recourse to the lamellar polarizatioa of Biot iu order to explain 

 the double refractiojj of Leucite. ^ 



On a Curve lUustrating the British Gold Coinage, 

 Bij W, Chandler Roberts, F.CS, 



On the Amount of Heat required to raise Elementary Bodies from the ahsolute 

 zero to their state of Fusion. By R. ScnEXK, Ph.D. 



The scale of absolute temperature is now so much used in the mechanical theory 

 of heat, that the[absolute zero of temperature has in some degree lost its hypothetical 

 character. Now, if we assume that a body at —273° is completely deprived of heat, 

 we can calculate the total heat present in it at any other temperature, provided that 

 we know either all or several of the following data — the specific heats in its three 

 states of aggregation and its latent heat of fusion and of vaporization, besides its 

 melting- and its boiling-point. As it aj^peared to me of interest to compare the total 

 heats possessed by different bodies in analogous conditions, I intended to calculate 

 them first for the gaseous state, as it was likely that any relationships existing 

 between them might then be exhibited in the most simple manner. Finding, how- 

 ever, that, with the exception of water, there is not a single body with regard to 

 which all the required data are known, I was obliged to confine myself to a few 

 elements, of which the specific heat in the solid state, the melting-point, and the 

 latent heat of fluidity have been determined. I calculated first the total amount 

 of heat required by these bodies to be raised from the absolute zero of temperature 

 just to the point of fusion, by multiplying their specific heat in the solid state into 

 the melting-point, as expressed in the absolute scale, and adding to the product the 

 latent heat of fusion. The results are given in the last column but one, but do not 

 seem to exhibit any peculiarities. That some of these numbers are almost exactly 

 half as great as otherS; may be mere chance. By multiplying the numbers which 



Substance. 



Melting point 

 from 



O'C. 



Zinc 



Cadmium 



Tin 



Lead 



Silver 



Bismuth , 



Mercurjf 



Iodine 



Sulphur 



Phosphorus 



Bromine 



Water 



Sodium Nitrate . . . , 

 Potassivmi Nitrate. 



4.3.3 



320 



235 



332 

 1000 



270 

 -39 



107 



115 

 44 



-7 

 



310-5 



330-5 



the ab- 

 solute 



706 

 593 

 508 

 005 

 1273 

 543 

 234 

 380 

 388 

 317 

 2G0 

 273 

 583-5 

 612-0 



Specific 



heat in 



the solid 



state. 



0-09555 

 005GG9 

 005623 

 0-0314 

 005701 

 0-0306 

 0-03192 

 005412 

 -20259 

 •18870 

 •08432 

 -505 

 -27821 

 -23875 



Latent 

 heat of 

 fusion 



28-1 

 13-6 

 14-25 



5-4 

 21-1 

 126 



2-82 

 11-7 



9-4 



5 



79 

 63 

 47-4 



Total Heat re- 

 quired to bring 

 atomic propor- 

 tions expressed in 

 grammes from 

 -273° to the 

 state of fusion. 



95-60 

 47-2 

 42-81 

 24-39 

 93-67 

 20-2 

 10-289 X 

 32-26 X 

 89 X 

 64-81 X 



216-865X 

 225-33 X 



11 



X 



65.2= 



112 : 



118 = 



207 = 



108 = 



210 = 



200 = 



127 = 



32 = 



31 = 



80 



18 = 



85 = 



101 = 



: 5280-4 

 : 5051-6 

 : 5048-73 

 :10116-36 

 : 6132 

 : 2057-8 

 : 4097-02 

 ■■ 2848 

 : 2009-1 



6-2 

 5-2 

 5-0 

 5-0 

 10-1 

 6-1 

 2-0 

 40 

 28 

 20 



: 3003-57 3-9 

 1915305 19-1 

 : 19543-5 19-5 



