VOL. LXII.] PHILOSOPHICAI, TRANSACTIONS- 273 



As no particular treatise had been published on these waters, and Dr. D. M. 

 wished to know their particular nature and contents, he wrote to his Grace the 

 Duke of Athol, whose seat of Dunkeld is within 14 or 15 miles of the wells, 

 begging the favour of him, to ask some of the medical people in the neighbour- 

 hood to examine them, and to send him an account of the result. And in 

 consequence his Grace was so obliging as to send him a letter from Dr. Wood, of 

 Perth, giving the following description of the Pitkeathly springs ; and afterwards 

 6 bottles of the water. 



" The spring rises in a very low marshy ground, undistinguishable from any 

 other ; but, by the taste of its water, it is generally believed to contain no 

 mineral principle, but a small proportion of marine salts. It acquires somewhat 

 of a putrid taste by keeping, but retains its purging quality ; and it keeps much 

 better in open, than in corked bottles. It purges gently, and without griping. 

 An adult person drinks commonly a bottle and a half or 2 bottles, in a morning. 

 In scrophulous and scorbutic habits, it is certainly a most useful water. A new 

 spring has been lately discovered about 200 or 300 yards from the old one, but 

 its waters seem to be much of the same strength and quality as the former." 



Dr. D. M. afterwards wrote to Dr. Wood, and begged to know of him what 

 proportion of sea salts these waters contained, and whether they had any mixture 

 of a bittern in their composition ; and he had the following answer, dated Oct. 1 7, 

 1770. " Since I received your letter, I evaporated a Scotch pint (4 lb.) of these 

 waters in a white stone basin, and I obtained 2 drs. of a salt, which always ran 

 per deliquium, and would not crystallize. I shall try it again in the summer, as 

 at this season the air, being much charged with watery particles, may have pre- 

 vented the crystallization. By dropping a solution of potash into 3 Scotch 

 pints (12 lb.) of the waters, I got 85 grs. of a very fine magnesia." 



The 6 bottles of this water which were sent to Dr. D. M., arriving at a time 

 when he was much engaged, they remained for several months in the hamper in 

 which they were originally packed ; and he did not try any experiment with the 

 water till the 2d of Oct., 1771- It was then clear and transparent as the purest 

 rock water, only it seemed to have some few particles of light earth swimming 

 through it. It had then a fetid sulphureous smell, resembling somewhat that 

 of a foul gun or of rotten eggs, and it tinged silver in the same way as sul- 

 phureous waters ; and it had a sulphureous and slight saltish taste. This fetid 

 sulphureous smell, taste, and property of tinging silver, which this as well as 

 most other salt waters acquire by keeping, he suspected to be owing to a 

 fermentation taking place in the water, and slightly uniting some of the fine 

 oily matter with some of the acid of the salts which these waters contain, and 

 thus forming a sulphureous vapour, which is volatile while they remain slightly 

 united, but which by a more intimate union would form a real fixed sulphur. 



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