238 New Patents. [March, 



The axes of the octohedral crystal of iodine instead of being 

 equal, are to each other in the proportion of the numbers 2, 3, and 

 4, so nearly that, in a body so volatile, it is scarcely possible to 

 detect an error in this estimate by the reflective goniometer, be- 

 cause tlie surfaces change by evaporation too rapidly for any precise 

 measurement of their mutual inclination. 



The form which most frequently appears in a section of this 

 octohedron parallel to the plane of its greatest and least axes, pre- 

 senting to view a rhombic plate' bevilled at each of its edges by two 

 narrow planes, which are inclined to each other at an angle of 

 about 120i°. 



From the frequent occurrence of this rhombic plate, (of which 

 the acute angle is about 53°,) some crystallographers may be dis- 

 posed to regard this surface as the terminal face of a rhombic 

 prism, of which the diagonals are 2 and 4, and its height 3 ; and 

 it is evident that all the modifications of the octohedron may with 

 equal facility be derived from this prism. 



I remain. Dear Sir, with great regard, 



Your obliged and obedient Servant, 

 Feb. 22, 1815. VVm. H. W01.LASTON. 



P. S. In the same Number of your Annals, p. 75? you have 

 noticed the discovery of chromate of iron in America, crystallized 

 in regular octohedrons found in serpentine. 



Permit me to add, that this rare mineral, which I believe has 

 not hitherto been observed in Britain, occurs also in the Serpentine 

 of Portsoy, having the same crystalline form, and tinging the ad- 

 jacent rock of the usual green colour of chrome. 



Article XIV. 1 



New Patents. \ 



Laeger DinoT, Paddington, Middlesex ; for certain improve- | 

 ments in the method or means of illuminating houses or places, by j 

 the combination of tallow or other inflammable materials. Nov. 

 10, 1814. I 



William Benecke, Deptford, Kent ; for the improved method j 

 of manufacturing verdigris, of the same quality as that known in ! 

 commerce by the name of French verdigris. Nov. 12, 1814. 



Horace Hall, Golden-square, London ; for an improved '. 

 method of preparing and spinning hemp, flax, and other substances. : 

 Communicated by a foreigner residing abroad. Nov. 17> 1814. 



Edward Massey, Coventry ; for his chronometers and pocket 

 watches. Nov. 17, 1S14. 



Robert Barlow, Francis-street, Souihwark, surgeon; for a 

 machine or instrument called the hydrostatic self-blowing machine. \ 

 Nov. 22, 1814. 



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