VOL. XXV.] PHILOSOPHICAL TRANSACTIONS. QQ 



much after the same manner, but somewhat less, and with some difference in 

 the masonry.* 



Some Queries for examining Mineral Waters. By Sir William Petty, Knight. 



N° 166, p. 802. 



1 . How much heavier than brandy ? 2. How much will common water reduce 

 its taste? 3. What quantity of salt on evaporation? 4. How much sugar, alum, 

 vitriol, nitre, &c. will dissolve in a pint of it ? 5. Whether any anlmalcula will 

 breed in it, and in how long time? 6. Whether fish, viz. trouts, eels, &c. will 

 live in it, and how long? 7. Whether it will hinder or promote the curdling of 

 milk and fermentation of liquors, &c.? 8. Whether soap will mingle with it? 

 g. Whether it will extract the dissolvable parts of herbs, roots, seeds, more or 

 less than other water? i. e. whether it be a more powerful menstruum ? 10, 

 How galls will change its colour ? 1 ] . How it will change the colour of syrup 

 of violets? 12. How it differs from other waters in receiving the colour of co- 

 chineal, saffron, violets, &c.? 13. How it boils dry pease? 14. How it washes 

 hands, boards, linen, &c.? 15. How it extracts malt in brewing? 16. How it 

 quenches thirst with meat or otherwise? \7 . Whether it purges? in what quan- 

 tity of time and with what symptoms? 18. Whether it promote urine, sweat, 

 or sleep, &c. 



Philosophical Solution of the Case of the young Man who became blind in the 

 Evening, inN" isg. By Dr. Wm. Briggs. Abridged and translated from 

 the Latin. N° 166, p. 804. 



It is universally known, that copious vapours, rarefied by the heat of the 

 sun, ascend in the day-time, and descend again after sunset, being condensed 

 by the cold; and hence the air near the surface of the earth must be thicker. 

 So likewise, perhaps the humours of the eyes of the young man may in the 

 evening become thicker and more turbid; like also as urine, by heat or cold, 

 becomes clear or turbid. So that, from such thickness of the humours, the 

 rays of light may be so refracted as hardly to reach the retina, or, if they do 

 reach it, act with too weak an impulse. 



Now, all the described phaenomena agree very well with this hypothesis. For, 

 in the first place, the young man has been always subject to this complaint from 

 his infancy, without any apparent disease in the eyes, the humours being af- 



• In the above-described structure, the upper arch is intended to act as a discharging piece, to take 

 off the weight of the superincumbent wall, and prevent it from forcing down the flat under arch, by 

 pushing out its jambs at A and B. 



02 



