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they were or might be known,, has been, and is perhaps at 

 prefent, the principal fource of our ignorance of the caufes that 

 produce, vary, or interrupt them. Moft meteorologifls content 

 themfelves with noting the diurnal ftate of the atmofphere in 

 the place of their refidence, without any reference to its ftate in 

 diftant countries 5 and thus, for want oi conceit, Juinfmgidi pugn ant 

 omnes v'lncuntur . 



5**. The negledl of obferving the fuperior currents of the 

 atmofphere, which may at prefent be deteded by tracing the direc- 

 tion of baloons, in all feafons. 



6". The negledt of maritime obfervations, which, being freeft 

 from all local influences, are by far the moft inftrudive, and 

 fliould, if poflible, be made in all degrees of longitude and latitude. 



However, many of thefe obftacles have of late been happily 

 removed. The proportion of moiflure in the atmofphere rela- 

 tively to its faturability, in its various ftates, whether of denfity 

 or temperature, can now be perfedly afcertained by the hygro- 

 meter of the late excellent Mr. De Sauffure, who has by the moft 

 extraordinary efforts of genius and labour improved that inftru- 

 ment, fo as to make it fpeak a language every where uniform 

 and intelligible ; a degree of perfedion' ever before thought un- 

 attainable. Nay, by a number of moft ingenious and delicate 



L 1 2 experiments 



