t 2 49 3 
I am not without Hopes they may have their Dies, 
when they fall into more able Hands. 
Yet I believe I may fay, that from them, and the 
Obfervations I made by a new Improvement of the 
Barometer , (for the fame Number of Years) I can 
generally foretel for a Day, or perhaps two, the Change, 
or what Continuance the Weather will have. 
And although fo many ingenious and curious Per- 
fons, lince the Invention of Torricellius s Barometer y 
have been improving and endeavouring to bring that 
Machine to Perfedion •, yet notwithstanding all their 
indefatigable Care and Pains, the Air that is inter- 
fpers'd and mix'd with all fluids, (of which Mercury 
is efteem'd one) has in fome meafure fruftrated their 
Labours, and it has remain'd imperfed : For whilft 
there are any fmall Quantities or Particles of Air re- 
maining in the Quickfilver, it will be conftantly fifing 
in hot Weather, and falling in cold : Which really 
perverts the very End and Delign of a Barometer , 
which fhould fhew the Prelfure of the Air, and fore- 
tel when either fair Weather or Rain is coming; in- 
ftead whereof it is in a great meafure a Thermometer , 
foretelling Heat inftead of fair , and Cold inftead of 
Rain and Jlormy Weather : And thefe Imperfedions 
have all the various forts of Barometers (more or lefs) 
that have hitherto been invented. 
The Barometer I am about to defcribe, is not diffe- 
rent in Form from fome ufually made, it being of the 
2 diagonal kind, from whence the more minute Alte- 
rations are more readily difcovered: Of this Form 
many have been made by the late Curious Operator 
Mr. Batricky who has, in his way, well deferv'd of 
the Curious j who, though he had done fo much to- 
I i z wards 
