VOL. XXX.] PHILOSOPHICAL TRANSACTIONS. 288 



have corrected this irregularity, and we hear of no such complaints, where they 

 observe a just regimen : and we all agree, that those waters are, in their own 

 nature binding, and often require some opening medicine. The quantities of 

 water drunk at Pyrmont are very large, often 2 or 3 English quarts. It is no 

 wonder that their weight forces them through the bowels; for any co nmon 

 water, drunk hastily, and in such quantity, will do the same. Whereas, if you 

 take this method, and will drink Pyrmont, or any other chalybeate waters, 

 leisurely, viz. a pint-glass in an hour, or rather 2 half-pint glasses, you may 

 drink 3 pints in so many hours without danger of losing them by dejection. 

 And if any one will be careful, and take this caution with him, he will scarcely 

 fail of success ; that is, let him be very quiet and still,* both in body and mind; 

 the less he stirs or walks, the better he will pass off his waters by urine. And 

 though this will appear a paradox, especially to those physicians who practise 

 abroad, and commend to their patients much action in walking, yet I know 

 I have both reason and experience on my side. 



Remarks on a Paper in the History of the Royal Academy of Sciences, for the 

 Year 1711, concerning the Cause of the Variation of the Barometer : to show 

 that the Way of accounting for it in that Paper is sufficient^ and that the 

 Experiment made use of to prove what is there asserted, does no way prove it. 

 By J. T. Desaguliers, M. A., F. R. S. N° 351, p. 570. 

 The paper is as follows : — " It appears by the barometer, that when it rains, 

 or a little before rain, the air commonly becomes lighter. That it must ram 

 when the air becomes lighter, it is easy to imagine; for the imperceivable parti- 

 cles of water, that swim about in the air in prodigious quantities, not being 

 sufficiently sustained when the air has lost a certain degree of its weight, begin 

 to fall, and several of them joining together in the fall, form drops of rain. 

 So when about half the air is drawn out of the recipient of the air-pump, and 

 consequently the remaining air is as weak again as at first, something like a 

 small rain falls. But why should the air become lighter ? One might imagine 

 that in the place where it rains, it may have lost some of its weight and bulk, 

 by means of the winds carrying away some part of it : but M. Leibnitz, in a 

 letter to the Abbot Bignon, gives a new and more ingenious reason for it.'* 



" He pretends that a body, which is in a fluid, weighs with that fluid, and 

 makes up part of its whole weight, so long as it is sustained in it; but if it 

 ceases to be sustained, and consequently falls, its weight no longer makes a 

 part of the weight of the liquid, which thus comes to weigh less. This may 



* Dr. S. is perhaps the only physician who ever forbade exercise during the use of the Pyrmont 

 or other chalybeate waters. 



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