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VOL. LXII.] PHILOSOPHICAL TRANSACTIONS. 275- 



process advanced, and afterwards 1 scr. more of thin lamellae, which, on 

 examining with a magnifying glass, appeared to be made up of small square 

 crystals; there remained a small quantity of a salt ley, which probably would 

 have yielded a few more such lamellae. » 



The liquor which remained after the first 2 parcels of salt were separated, was 

 next evaporated; but no pellicle appearing, the operation was continued till it 

 was quite dry, when it formed one transparent yellow or amber-coloured salt 

 cake, which weighed 1 dr. and 34 grs. This salt, on being put into a tea cup, 

 presently began to run per deliquium, and dissolved entirely by standing in a 

 cupboard in a room where there was a fire ; but the fire having been let out in 

 the evening, and the night proving cold, he found next morning that a crystal- 

 lization had taken place, for there was a crystallized cake at the bottom of the 

 cup, which was covered with an amber coloured ley; it at first seemed to be all 

 one piece, with a number of small points standing on its surfaces; but on 

 reclining the tea cup to a side, it then appeared to be made entirely up of a 

 number of oblong crystals about the length of a barleycorn, but not so thick, 

 and that the points before-mentioned were the ends of these crystals. Not 

 having time to examine them particularly in the morning, and to know their exact 

 figure and number of sides, he set them by, till he should come home again 

 about 1 o'clock; but the day proving warm, they were mostly dissolved before 

 tiiat time. 



Oil of vitriol, dropped into a tea cup in which there was some of this ley, 

 immediately occasioned a white firm coagulum like chalk, which was insoluble in 

 water, and, when well washed and freed of its acid, felt gritty, and was quite 

 insipid in the mouth ; this is certainly a selenites formed by the earth of this ley 

 and the vitriolic acid. 



From this account of the Pitkeathly waters, it appears, says Dr. D. M., that 

 6 lb. 6 oz. 3 dr. 1 scr. besides a few grains of an absorbent or calcarious earth, 

 contain 3 drs. 41-Lgrs. (besides what was lost in filtrating and other operations) 

 of a saline matter, of which near f were sea salt, the rest a bittern or salt with 

 an earthy basis, which concreted by the force of fire into a yellowish saline mass, 

 that runs soon per deliquium, and crystallizes though with difficulty. The 

 small quantity he had of residuum prevented him from determining with pre- 

 cision, the exact proportion of sea salt and of this bittern ; neither was he for 

 the same reason, able to determine whether this bittern or ley was all made up 

 of a calcarious marine, with on oily matter common to all waters, or whether 

 it contained likewise a sal catharticum amarum with a vitriolic acid. From the 

 acid of vitriol forming an insoluble selenites with the earthy basis of this bittern, 

 it is evident, that at least all the earthy basis is not a magnesia, such as makes 



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