aOO PHILOSOPHICAL TRANSACTIONS. [aNNO 1738. 



4. If they show for rain, you may by them distinguish whether it will be 

 little or much. 



5. As by other barometers you cannot tell the weather, but by a past and a 

 present observation ; these tell, the moment you come to them, what the 

 weather is going to be : for by tapping the case with your finger, if it is going 

 to be fair, or very fair weather, the mercury will rise that moment a 10th of an 

 inch, or more : but if for foul, it will scarcely make any sensible rise. 



Remarks. — 1 . Though you can foretel it will rain on the morrow, it is im- 

 possible to tell where that rain will fall : for as every shower has space, i. e. 

 length and breadth, if it rains in that particular field, yet it may be fair in the 

 next adjoining : and if in harvest, or on a journey, you proclaim it will rain on 

 the morrow, some will, if it does not fall on their land, or on their coat, be so 

 silly as to say the prediction was false. 



1. The barometer only shows the pressure or weight of the atmosphere, and 

 inclination of the air, in and about the country where it stands, and not always 

 in a particular spot : so that in foretelling of great rains, people are apt to say 

 the indication is false, because they have not seen or heard of it; when perhaps 

 in a day or two you will hear, that it did then fall 3, 4, or perhaps 10 miles off. 

 p'or though the rain should be over us when the glass fell, yet the wind, which 

 bloweth where it listeth, cjirries the clouds and rain with it. 



3. It is very hard to distinguish on the mercury's falling, whether it will be 

 rain or high winds, these equally causing the mercury to subside. 



4. Of all those who guess at the weather from the whims of their own brains, 

 it is observable, it is not true one time in ten, nor do any two of them agree 

 about it. But from observations on this barometer, it will seldom fail you once 

 in 20 ; so that it is above 100 to 1 preferable. 



5. If from the state of the mercury yesterday and this morning, it be pro- 

 nounced the next day will be no rain, and we look, at the glass no more to-day; 

 perhaps winds may arise, and so alter the atmosphere's weight, and the glass 

 falls much, it will rain on the morrow, contrary to what was at first expected. 

 Here it is plain, had the glass been seen again in the afternoon, the rain might 

 have also been foreseen. 



Hence it is evident from these remarks, that judgments are taken on the 

 weather from barometers, which do not prove so; and this produces opinions in 

 the vulgar and ignorant, that there is no judgment at all to be had from them. 



If the barometer could only foretel very great and remarkable changes of the 

 weather ; for instance, in harvest-time, that a very great rain, or perhaps 

 floods, were coming ; the husbandman would stop cutting down his grain, and 

 save some of it being spoiled by the wet : or on a journey, if I know that if I 



