412 On thespedjic Gravil'ies of the Gases, 



requisite to elicit the magnitude of all the equations, which re- 

 gulate the inequalities in the lunar motions. 



If the revisers of the lunar theory had not been more suc- 

 cessful in their efforts than Mr, Yeates towards cultivating more 

 perfectly the lunar astrmioniy, the .science would have been ex- 

 tremely low in the scale of improvement, compared with its 

 present elevation. 



I remain, sir, yours truly, 



Norfolk-street, Lynn Regis, JaMES UttING. 



Dec. 4, 1820. 



P. S. With the Editor's permission, I l>eg leave to express 

 my sentiments of esteem, being principally indebted to the works 

 of Dr. Hutton for that information which I have acquired in 

 the sciences, and by my own application only. I sincerely con- 

 gratulate this gentleman on the receipt of the very respectful 

 letter from the Marquis De Laplace, confirming the truth and 

 originality of the very laborious and intricate Calculations of the 

 mean Density of the Earth, and confirming beyond all doubt 

 the universal attraction of matter ! ! ! J. U. 



LXVII. On the Specific Gravities of the Gases, and the different 

 Musical Sounds ivhick they occasion in the same Organ- 

 Pipe. By Mr. John Farey Seti. 



To Mr. Tilloch. 



Sir, — 1. HAVE on two occasions* endeavoured to call the at- 

 tention ofatiy Experimentalists, who miglit have the Opportunities 

 which I myself do not possess, and who might be so inclined, to 

 the trying experimentally, of the truth of that theory, which 

 assigns Gtt Intervalletween the Sounds produced in a given Pipe, 

 ly two different Gases, ivhich is measured Inj the inverse Sub- 

 duplicate Ratio of the specific Gravities of these Gases. 



At the periods to which I allude, sufficient precision had not 

 been given to the experimental determinations of the specific 

 Gravities, of many of the Gases, but which important data, have 

 now lately been supplied, by our eminent and indefatigable che 

 mist. Dr. Thomson, of Glasgow ; who has taken the utmost care 

 in procuring 26 different Gases, unmixed, and in a state of purity, 

 and in weighing these Gases, and calculating their specific Gra- 

 vities, in which latter operation, he has availed himself (in all 



* P. M. vol. xxxvii. p. 3, and Edin. Ency. vol. x. p. 120, 



but 



