A^ PHILOSOPHICAL TRANSACTIONS. [aNNO 1672. 



As to the whole matter, that it will be hard to lay down any perfect theory of 

 winds, in regard that the great inequalities in the superficies of the earth ; the 

 several obstacles and repercussions from mountains ; the different situations of 

 the places and mediums in which they blow; the distance of those countries 

 from the poles of the world; their respects to the course of the sun, whether 

 they comply with, or resist the natural motion of the air from east to west, &c. j 

 have many intricate and nice speculations, not easy to be stated. 



II. Deux Machines propres a faire les Quadrans, avec tresgrande facilite; 

 par le P. Ignace Gaston Pardies, S.J. A Par. 1673, in 12mo. 



The author of these two machines thinks they are sufficient for any person, 

 by their means, to learn the whole theory and practice of dialing, and that in 

 less than an hour's time; and may practice what he so learns, as it were by play, 

 drawing the dials on walls, and in his chamber, with the greatest ease. 



A New Experiment concerning an Effect of the Varying PPeight of the Atmos- 

 phere on some Bodies in the water. By R. Boyle, Esq. N° Ql, p. 5156. 



I am prone to suspect, that the alterations of the atmosphere in point of 

 weight may, in some cases, have some considerable effects even on men's 

 health; as when the ambient air, for instance, grows suddenly very much 

 lighter than it was before, or than it was wont to be, the spirituous and aerial 

 particles, that are plentifully harboured in the mass of blood, will naturally 

 swell that liquor, and so may distend the greater vessels, and not a little alter 

 the celerity and manner of the circulation of the blood by the capillary arteries 

 and veins. To countenance this conjecture of mine, I will annex an experiment 

 that you will not perhaps dislike, just as I find it registered among some of my 

 loose papers. 



I caused to be blown at the flame of a lamp three small round glass-bubbles, 

 about the size of hazel nuts, and furnished each of them with a short and 

 slender stem, by means of which they were so nicely poised in water, that 

 a very small change of weight would make them either emerge, if they but 

 lightly leaned on the bottom of the vessel, or sink, if they floated on the top of 

 the water. 



This being done at a time when the atmosphere was of a convenient weight, 

 I put them in a wide-mouthed glass furnished with common water, and suffering 

 them to continue many weeks, or some months, I observed, as I expected, that 

 sometimes they would be at the top of the water, and remain there for divers 

 days, or perhaps weeks ; and sometimes would fall to the bottom, and after 



