58 Account of a new Eudiometer, 



Auguft, and September, 1800, with phofphorus, fulphurets 

 of alkalies, and impregnated folution, demonftrated the ac- 

 curacy of the proedfes in which the laft fubftance was pro- 

 perly employed. The diminutions given by the fulphurets 

 were indeed always greater, by a minute quantity, than thofe 

 produced by phofphorus and impregnated folutions: but the 

 reafon of this will be obvious to thofe who have ftudied the 

 fubject of Eudiometry. In no inftancc was it found that 

 ioo parts in volume of air contained more than 1\ of oxy- 

 gen : and the variations connected with different winds, 

 and different ftates of temperature, moifture, &c. were too 

 fmall, and too often related to accidental circumftances, to 

 be accurately noticed. 



In analyfmg the atmofphere in different places, by means 

 of impregnated folutions, I have never been able to afcertain 

 any notable difference in the proportions of its conftituent 

 parts. Air, collected on the fea at the mouth of the Severn, 

 on October the 3d, 1800, which muft have palled over much 

 of the Atlantic, as the wind was blowing ftrong fyom the weft, 

 was found to contain 21 percent, of oxygen in volume; and 

 this was nearly the proportion in air fent from the coaft of 

 Guinea, to Dr. Beddoes, by two furgeons of Liverpool. 



If we compare thefe refults with the refults gained more 

 than twenty years ago, by Mr. Cavendim, from experiments 

 on the compofition of atmofpherical air, made at London 

 and Kenfington ; confidering, at the fame time, the re- 

 searches of Berthollet in Egypt and at Paris, and thofe of 

 Marti in Spain, we {hall find ftrong reafons for concluding 

 that the atmofphere, in all places expofed to the influence 

 of the winds, contains very nearly the fame proportions of 

 oxygen and nitrogen : a circumftance of great importance ; 

 for, by teaching us that the different degrees of falubrity of 

 air do not depend upon differences in the quantities of its 

 principal conftituent parts, it ought to induce us to inftitute 

 jefearches concerning the different fubftances capable of 

 being diffolved or fufpended in the air, which are noxious 

 to the human conftitution ; particularly as an accurate know- 

 ledge of their nature and properties would probably enable 

 us, in a great meafure, to guard againlt, or deftroy, their 

 baneful effects. 



Xt An 



