Dr. Heddle's Analysis of Lunnite from Cornwall. 39 

 when the coucentration of the upper solution was decreased from 

 saturation to 2 per cent. My own experiments m the same 

 direction with common salt gave a purely negative result, as the 

 equivalent was not perceptibly decreased. 



The comparison of the experiments adduced above with the 

 hypothesis developed on the foundation of the diffusion law, 

 shows, though not absolutely, that the truth of this ^potlaesis 

 may be determined; and it is in fact highly probable that, with 

 or without modification, such an hj^^othesis may serve as the 

 foundation of a subsequent theory of these very dark ph^- 



nomena. 



VI. Analysis of Lunnite from Cornwall. 

 By Dr. Heddle*. 



THIS mineral was sent me for analysis by Mr. Greg, under 

 the hope that it might prove to be a new phosphate of 

 copper. It is doubtful from which of the Cornish mmes it was 

 procured, and the specimen m Mr. Greg's collection is, as far as 

 is kno\vn, the only one which was found. ^ • , 



The specimen consists of aggregated congeries of minute 

 spheres, the structure of which is radiated. The specific gravity 

 is 4-25; little dependence can, however, be placed upon this 

 determination, as it was found impossible to free the specimen 

 from air, and minute crystals of quartz were imbedded m the 



"'The powdered mineral absorbs -28 per cent, of moisture. 

 Analysis of 34 grs. :— 



Oxide of copper .. 68-13 



Phosphoric acid • . 22*73 



Water ^'51 



Silica '48 



99-85 



The silica was mechanically mixed. i • „ 



This substance occurs in few localities. By this ana ysis a 



new one is given, and the mineral is now for the fiist time 



noticed as a British species. 



* Communicated by the Author. 



