232 Miscellaneous Intelligence. 



more sensible to electric changes, but neither did he experience 

 any change in his feelings at the moment. — Annales de Chimie, 

 xxxiii. 417. 



7. Phosphorescence ofFluateofLime. — Fluate of lime, though a 

 highly phosphorescent substance, requires either to be heated or 

 rubbed, for the emission of the light. A fluate of lime obtained 

 from Odonschclon, in Daourie, was, however, found to be luminous 

 without this preparation, the light being of such intensity as to ren- 

 der the piece visible without being placed in perfect obscurity. Its 

 luminous state has continued ever since, and nothing indicates that 

 it will cease. The intensity of the light is not always the same, and 

 appears to be changed by changes in the atmosphere ; it is greatest 

 in wet and stormy weather. The contact of air appears to exert 

 an influence on the light, for pieces of the fluor closed in a drawer 

 for eight days, were found scarcely luminous, but being exposed to 

 air became equally brilliant as at first. When plunged into water 

 the degree of phosphorescence appeared to be much more constant. 

 The light was of a feeble yellowish-green colour; a piece of the 

 substance two inches in diameter gave light sufficient to permit 

 words to be read at some lines distance. According to the obser- 

 vations of M. Becquerel, heat has great influence over the phos- 

 phorescence: at zero the light is scarcely visible ; plunged into boil- 

 ing water, it became very luminous ; upon mercury heated to 300° 

 C.(572°F.), the light was so strong as to allow printed characters to 

 be read at seven inches and a half distance. This high temperature 

 injured the phosphorescent power of the substance at common tem- 

 peratures for a short time ; but it was restored to its full intensity 

 by exposure for a few hours to solar light : finally, it appeared 

 that atmospheric causes, not as yet understood, exert a great influ- 

 ence upon the substance. 



The object of the note is to point out the curious property pos- 

 sessed by this fluate of lime, of remaining permanently luminous. 

 It is found in a primitive granitic rock, in company with beryl, 

 topaz, wolfram, &c., and differs, in appearance, from the ordinary 

 varities of fluor spar, by its peculiar waxy or resinous lustre. It is 

 found massive, having a structure more interlaced than the ordi- 

 nary varieties, and sometimes crystallised ; it then has very com- 

 plicated forms.— Bull. Philomat. 1826, 104. 



8. Chemical Compounds produced by physical Powers. — " Sitting 

 of the Royal Academy of Sciences at Paris, 11th December, 1826. 

 M. Becquerel announced, that he had succeeded in producing new 

 compounds, by means of physical powers only. Each of the new 

 compounds has a peculiar crystalline system, and most of them have 

 the property of being decomposed by water." — Annales de Chimie, 

 xxxiii. 439. 



9. Table of the Density of Vapours and GaseSt examined by M. 



