igS PHILOSOPHICAL TRAKSACTIONS. [aNNO 1738. 



The Imperfections of the Common Barometers, and the Improvement made in 

 them by Mr. Cha. Orme oj jishby-de-la-Zouche. IVith some Observations, 

 Remarks, and Rules for their Use. By Mr. Henry Beighton, F. R. S. 

 N° 448, p. 248. 



Nothing is more wanted than a theory of the weather on mechanic princi- 

 ples ; and nothing in all philosophy see:iis of more immediate concern, than the 

 state of it. In order to this, a complete history of the weather is necessary, 

 from thence to deduce such rules and observations as may in some measure form 

 such a theory : and could we in any tolerable degree foretel, but by some small 

 space of time, the change of the weather, it would be of admirable use, in 

 those affairs on which the chief part of our welfare and subsistence depends. 



It was from such considerations, that more than 20 years ago Mr. B. began, 

 and has continued, to keep a diary of the weather, the last 6 years of which are 

 here subjoined ; but cannot think, himself so well qualified, as to form a just 

 theory on them, though they may have their uses, when they fall into more 

 able hands. Yet he thinks he can generally foretel for a day, or perhaps two, 

 the change, or what continuance the weather will have. 



And though so many ingenious persons, since the invention of Torricelli's 

 barometer, have been endeavouring to bring that machine to perfection ; yet 

 notwithstanding all their care and pains, the air interspersed and mixed with all 

 fluids, has in some measure frustrated their labours, and it has remained im- 

 perfect : for while there are any small quantities or particles of air remaining in 

 the quicksilver, it will be constantly rising in hot weather, and falling in cold : 

 which really perverts the very end and design of a barometer, which should 

 show the pressure of the air, and foretel when either fair weather or rain is 

 coming ; instead of which it is in a great measure a thermometer, foretelling 

 heat instead of fair, and cold instead of rain and stormy weather : and these 

 imperfections, more or less, attend all the various sorts of barometers, that have 

 hitherto been invented. 



The barometer here described, is not different in form from some usually 

 made, it being of the diagonal kind, from whence the more minute alterations 

 are more readily discovered: of this form many have been made, by the late 

 curious operator Mr. Patrick, who has, in his way, well deserved of the curious; 

 who, though he had done so much towards the proving the weight of the 

 atmosphere by which the mercury in the tube was sustained, he himself did not 

 believe it, but ran into the absurdity of the funicular hypothesis. 



There is an inconveniency or imperfection in most, if not all, of those 



