4f3Q GASES IN "IHE ATMOSPHERE. 



which may be eafily proved by examining the going of my 

 timekeepers. It will there appear that what errors, they arc 

 fubje6l to, arife from caufes certain and natural, and in courfe 

 may be corredted by art*. 



IX. 



Experimental Enquirj/ into the Proportion of the fereral Gafes or 

 Elajlic Fluids, conjlituting ike Atmnfphere. 5y J o h n D a l t o N . t 



On ihz compo- J[]SJ a former paper which I fubmitled to this fociety, "on the 

 th"atmofrhcrc. conftitution oF mixed gafes," I adopted fuch proportions of 

 the fimple elaftic fluids to conflilute (he atmofphere as were 

 then current, not intending to warrant (he accuracy of them 

 all, as ftated in the faid paper j my principal objed in that 

 eflay was, to point out {\\& manner in which mixed elaflic fluids 

 exift together, and to infift upon what I think a very important 

 and /undarnenfal ppfition in the do61rine of fuch fluids: — 

 liamely, that the elaftic or repuifive power of each particle 

 is confined to thofe of its own kind"; and cohfequenfly the 

 force of fuch fluid, retained in a given veflel, or gravitating, 

 is the fame in a feparate as in a mixed flale, depending upon 

 its proper denfity and temperature. Tiiis principle accords 

 with all experience, and I have no doubt will foon be per- 

 ceived and acknowledged by chemifts and philofophers in 

 general; and its application will elucidate a variety of facls^ 

 which are otherwife involved in obfcurity. 

 Ohjeas of this Ti,e obje6ts of the prefent eflay are, 



i/to deter- l.To determine tlie weight of each fimple atmofpherej 



Kime ihe weight abftractediy ; or, in other words, what part of the weight o 

 mofphereV* ' ^^^ whole compound atmofphere is due to azote; what to 

 oxygen, &c. &c. 



ind the re- 2. To determine the relative weights of Ihe different gafes 



htive weights of in a given volume of atmofpheric air, luch as it is at the earth's 



of the gafes at r r 



the fuiface of lunace. 



iki- earth 



* To this communication Mr. EaniHiaw has annexed two plates 

 with defcriptions, tliewing the parts of his time-piece ; all whichj. 

 except thoi'e of the Efcapement (which we hnve given) are capable 

 f)f the fame variations as thofe of any other good movements. He. 

 alTerts that the beft train for time keepers is 18,000 ; that the fcape 

 wheel for pocket ones fliould have 15 teeth, and for box ones 13 



teeth. 



+ Manchefter Mem. Vol. V. 



13. Cj 



