366 Mr» Meikle on the Law of Temperature. [Nov. 



among which I shall mention cymophane, peridot, humite, fos- 

 terite, crystallized serpentine, tantalite, &c. the results of which 

 I shall publish when completed ; and I hope that as the number 

 of examples of isomorphisms will increase, the attention of 

 mineralogists and chemists may be directed to this interesting 

 subject, which require the help of both. 



1 shall also avail myself of this opportunity to give the 

 description of a beautiful crystal of tungstate of lime, which 

 belongs to the collection of the Right Honourable the Dowager 

 Countess of Aylesford, and which her ladyship has allowed me 

 to examine, dy comparing its measurements with those pre- 

 cedingly given for tungstate of lead, the analogy between these 

 two substances will appear. The form is represented by fig. 2, 

 and the crystal is nearly of the size of the figure, and perfect. I 

 have assumed for primitive the square prism represented by fig. 3, 

 in which the side b of the base is to the height as 1 is to 2-098. 



Fig. 3. 



^ 



h : g:: 1 : 2-098. 



^fl, b = 151° 33'. ,fl, a" = 152° 21'. s> «* = 136° 12'. 



This magnificent crystal is of a pale yellowish colour, and 

 transparent. Mr. Heuland, on seeing the specimen to which it 

 is attached, had no doubt that its locahty was Breitenbrunn, 

 in Saxony. 



Article XI. 



On the Law of Temperature. By Mr. Meikle. 

 (To the Editors o{\\iQAnnah of Philosophy.) 



GENTLEMEN, Edinburgh, Sept. 30, 1826. 



In the last number of the Edinburgh New Philosophical 

 Journal, I had occasion to point out some very remarkable 



