VOL. LXXXI.] PHILOSOPHICAL TRANSACTIONS. 6l 



XIV. Experiments on Human Calculi. By Mr. Timothy Lane. F. R. S. p. 223. 



The lixivium saponarium of the late pharmacopoeia, prepared with the addi- 

 tion of so much lime as nearly to free the salt of tartar of its fixed air, having 

 been used as a medicine for the stone and gravel some years before, and its effects 

 found very unequal, Mr. L. thought it necessary to examine different calculi, 

 then collected, both as to the effect of the above lixivium, and of fire, on them. 



Great disparity was observed ; some being dissolved, and others scarcely 

 altered in their figure. When tried by fire, some were nearly evaporated by a 

 red heat, and others retained their form. Different parts even of the same cal- 

 culus varied considerably. To be better informed of the above, the experi- 

 ments were repeated both by fire and lixivium, with greater accuracy, as follows: 

 14 specimens were selected, some of which were parts of the same calculus, 

 and others different calculi. In the experiments by fire he was favoured with the 

 assistance of Mr. Stanesby Alchorne, of the Tower, to whom were sent lOgrs. 

 of each, in separate papers, which were numbered. 



The contents of each paper were placed in separate cupels, under a muffle, 

 the same 'as is used by him for assaying gold and silver. The fire was raised 

 gradually, till the furnace was fully heated : the time from raising the fire to the 

 taking them out again was 3 hours, when it was concluded, that whatever vola- 

 tile matter they contained was expelled. The same quantity as above, of each 

 specimen, being put, into separate numbered phials, with 1 oz. measure of the 

 lixivium in each, continued 48 hours ; the phials were frequently shaken to for- 

 ward the solution. The clear liquor of each phial was decanted into fresh phials, 

 and \ oz. more lixivium was added to such as were undissolved ; after 24 hours 

 they were poured out of the phials into separate filtering papers, each numbered, 

 and the phials washed with distilled water, which was also poured into the papers, 

 so that all that remained undissolved might be detained by the papers, which 

 with their contents were carefully dried. 



Jppearances of each after calcination.— N° 1 , ^he remains of each. 



3, 7, 8, left a fine white and soft powder. Unsublimed. Undissolved. 



N° 4, 5, 11, 12, left a white and gritty 

 powder. N° 



N° 2, 6, 9, 10, 14, were partly in powder 

 white and gritty, with some lumps of a dark 

 colour, as if not fully calcined. 



N° 13. Of this the figure was not greatly al- 

 tered ; it remained hard, and part of it ap- 

 peared as if inclined to flux. 



^fter being in the lixivium about 48 hours. — 



N° 8, 9, 13, 14, were found soft. 



N° 7 and 10 remained hard. 



