VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. SQ 



was relieved from his former complaints, has enjoyed and does yet enjoy the 

 most perfect health. 



In the year 1754, the author became possessed of a calculus, which was of a 

 flinty hardness, and bore a bright polish. It weighed a quarter of an oz. He 

 conjectured, that a much longer time would be necessary to dissolve this stone ; 

 but, what was very remarkable, it dissolved sooner than the rest : for after having 

 been immersed 24 hours, 2 grs. of it only remained undissolved. This stone 

 was not placed in the China basin as the others were, but suspended in a little 

 loose-woven net, that it might more freely be washed by the water. Dr. Lie- 

 berkuhn was at this time at Carlsbad ; he was present at this experiment, and 

 was witness of its truth. The net used in this experiment was covered with a 

 tophaceous crust, from being steeped in the water. 



The next year, when Dr. Lieberkuhn returned to Carlsbad, he brought with 

 him, for experiment sake, several calculi, some of which were large ones. He 

 made there many experiments, in which our author assisted. A large stone was 

 sawed into 4 pieces, nearly equal. One of these weighing QQ grs. was put into a 

 little linen bag, and immersed in the source called Prudel : the 2nd in like man- 

 ner, which weighed 96 grs. into that called the new spring : the 3d, weighing 

 93 grs. into that near the mill : the 4th was set apart for other trials. After 4 

 days immersion they were severally examined. The first had lost 85 grs. the 2d, 

 33 grs. the 3d, only 16 grs. That it might be estimated in what degree the 

 solvent power of the Carlsbad water exceeded that of lime-water, the following 

 experiment was tried. Three pieces of calculi, each exactly 30 grs. in weight, 

 were put into separate phials. On one was poured some fresh egg-shell lime- 

 water : on the 2d some Carlsbad water : on the 3d, some of the urine of a person 

 daily drinking these waters for the recovery of his health. These phials were all 

 placed in one of the canals, which carries off the waste water from the baths : 

 the degree of heat in this place was by Fahrenheit's thermometer 96, much the 

 same as the heat of human blood. The lime-water, the Carlsbad water, and 

 the urine, were changed every day, and the process continued for J 4 days. On 

 the 15th, the remaining fragments of stone were taken out of the phials, and 

 weighed when dried. The piece macerated in lime-water had lost 1 gr. that in 

 the Carlsbad water, 6 grs. that in the urine, 5 grs. According therefore to 

 this experiment, the solvent power of the Carlsbad water was 6 times, that of 

 the urine 5 times greater than that of the lime-water. 



The solvent power of medicated urine is of very great importance, and re- 

 quires more particular attention ; as our greatest expectations in dissolving the 

 stone in the bladder must arise from that. It was therefore very fit that our 

 author should investigate, as far as was in his power, the solvent property of the 

 urine of those who drank these waters. He therefore suspended to the end of a 



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