VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 63Q 



room, for other important purposes ; but also in procuring fresh sweet wholesome 

 water, instead of stinking putrid water, hitherto used ; which must needs have a 

 tendency to promote that putrid distemper, the scurvy. And if due care be taken 

 to exchange for fresh air, the putrid close confined air of ships, which has occa- 

 sioned the death of millions of mankind ; then navigation will become more 

 healthy, and with little more danger to health and life than at land, except from 

 storms. 



Dr. H. distilled 3 gallons of sea-water, with the proportion of 6 oz. of Mr. 

 Appleby's lapis infernalis, and 6 oz. of calcined bones to 20 gallons of sea- 

 water, as he directs. This water lathered well with soap, and boiled peas well. 

 He distilled also some sea-water with half an ounce of stone-lime to a gallon, from 

 the Clee hills in Herefordshire, which having been preserved 10 months in a 

 firkin, had slackened to dry powder. This distilled water also lathered well with 

 soap, and boiled peas well ; which proves that the lime, which is a fixed body, 

 does not distil over with the water. Afterwards General Oglethorpe informed 

 him, that his father. Sir Theophilus, told him, that lime was one of the ingre- 

 dients, which he and the rest of the patentees, in Charles the second's time, called 

 the cement, with which they made distilled sea-water wholesome. He distilled 

 also some sea-water with the like proportion of powdered chalk, which boiled peas 

 well, and was better tasted than the waters distilled with lapis infernalis, or lime. 

 He distilled also some sea-water with an ounce of chalk to a gallon, but found no 

 difference in the taste of this, and that which had but half an ounce of chalk to a 

 gallon: so that half an ounce of chalk to a gallon of water will be sufficient; but 

 where the sea-water is Salter, or more bituminous, more chalk may be added if 

 needful. 



Dr. Alston, of Edinburgh, in the preface to the 2d edition of his Dissertation 

 en Quick-lime and Lime-water, says. That " the like effect was found in distill- 

 ing sea- water with lime; that it neither precipitated a solution of silver in aqua- 

 fortis, nor a solution of corrosive sublimate in water, nor did it form a pellicle of 

 various colours on its surface, as did the water distilled by Mr. Appleby's process." 

 And indeed lime of oyster-shells had the same good effect, but required two dis- 

 tillations, perhaps by using it in loo small a proportion. Hence it is probable, that 

 the chalk, the lime, the lime in the lapis infernalis, and the lime in Dr. Butler's 

 soap-lees, seize on and fix not only the bittern salt, but also the bitumen of the 

 sea-water, as we learn from the like effect in the purification of the salt of harts- 

 horn. That the saline spirit arises chiefly from the bittern salt, and not from 

 the more perfect sea-salt, is probable from hence, viz. That in distilled 3 gallons 

 of common water, made as salt as sea-water with common salt; no spirit of salt 

 arose, even though the distillation was carried so far as to leave the salt, though 

 very damp, to lie in heaps, and it was incrusted on the sides of the still, for about 

 3 inches from the bottom. 



