242 ' DISSERTATION on the 



2,tio, In confulting the analogy of nature, one cannot fail to 

 recollect, that all known bodies poffefs, befides the Newtonian 

 attraction, which is common and general to them all, another 

 attractive force, or that which produces cohefion between two 

 pieces of poliihed marble, the afcent of fluids in capillary tubes, 

 and an infinite number of other phenomena. Now, this laft 

 attractive force is evidently and efTentially different from the 

 firft ; for whilft the one follows the inverfe ratio of the fquare 

 of the diftance, it is proved that the other is in proportion to a 

 power, into which enters the reverfe ratio of the cubes, and 

 probably of fome ftill higher ppwer of the diftance. 



If then both experience and the analogy of nature, (how the 

 poflibility of the co-exiftence of two attractive forces in the 

 fame body, governed by laws entirely different 5 and as a repul- 

 five force is nothing elfe than a negative attractive one, my fup- 

 pofltion of the repuliive force of bodies, contains nothing but 

 what is perfectly conformable to the analogy of nature. 



You alfo make mention, Sir, and with reafon, of the frequent 

 appearance of the beautiful phenomena of parheliums and 

 mock moons in our climate, which enables us to be better ac- 

 quainted with all the circumftances attending them, than people 

 nearer the equator. I paid a particular attention to thefe phe- 

 nomena for a part of the years 1 758 and 1 759, and I think I have 

 made fome important obfervations on that fubject ; but it is not 

 at prefent either the time or place to enter into them, efpecially 

 as I have already given the principal facts in a paper inferted in 

 the eighth volume of the Novi Comment. Academ. Scien. Petrop. 

 p. 392, by referring to which I fhall content myfelf at prefent. 



It is now time, Sir, to finifh this long letter, which has al- 

 moft fwelled to a differtation ; and I fhall do fo, by affuring 

 you, that I am, with much efteem, 



Your obedient fervant, 



St Petersburg, 7 

 Jan. 7—18. 17S9. $ 



iEpi NUS. 



SIR, 



