Dr. Dalton on the Constitution of the Atmosphere. 195 



Society on the 9th and 16th of February last* ; and having made 

 in it several alterations and additions, consisting chiefly in notices 

 of the discoveries of preceding anatomists in the same field of in- 

 quiry, again presents it to the Society, with these improvements. 



f Sequel to an Essay on the Constitution of the Atmosphere 

 published in the Philosophical Transactions for 1826 f j with some ac- 

 count of the Sulphuretsof Lime;" by John Dalton, D.C.L., F.R.S. 



The author communicates in this paper an account of the inves- 

 tigations on the constitution of the atmosphere, which have engaged 

 his attention during a long period of years. He enters into an ex- 

 amination of the comparative advantages of the three methods which 

 are most in use for analysing common air, namely, firing it with hy- 

 drogen in Volta's eudiometer, or abstracting the oxygen by means 

 of nitrous gas and quadrisulphuret of lime ; and details the pre- 

 cautions to be taken in the employment of each of these methods, 

 and the degree of accuracy to be expected from the results under dif- 

 ferent circumstances. He then relates numerous experiments made 

 on air obtained from great heights, from which he is led to the con- 

 clusion that the proportion of oxygen to azote in the atmosphere on 

 the surface of the earth is not precisely the same at all places and 

 times ; and that in elevated regions this proportion is somewhat less 

 than at the surface of the earth, but not nearly so much as the 

 theory of mixed gases would require, and that the reason for this is 

 to be found in the incessant agitation of the atmosphere produced 

 by winds and other causes. 



" Researches on the Tides. Eighth Series. On the progress of the 

 Diurnal-Inequality-wave along the coasts of Europe." By the Rev. 

 William Whewell, F.R.S. , &c. 



In the seventh series of these researches J, the author pointed out 

 the laws which the diurnal inequality of the height of high water 

 follows, and showed that those laws are modified so as to exhibit very 

 remarkable differences at different places, and to occasion some 

 difficulty in conceiving the mechanical propagation of the tide-wave. 

 He then suggested what appeared to be a possible solution of the 

 difficulty j but as this suggestion was founded on facts from a few 

 places only, he resolved to attempt to trace the progress of the 

 wave which brings the diurnal inequality on some of the coasts, on 

 which simultaneous observations were made at his request in June 

 1835; and the present memoir contains an account of the conclu- 

 sions to which he has been led by this investigation. The details 

 which he gives of the observations made, with this view, at nineteen 

 different stations, appear to establish the conclusion, that the differ- 

 ences of diurnal inequalities at different places are governed by local 

 circumstances, and do not form a progressive series. 



" Note on the Fluctuations of the Height of High-water due to 

 changes in the Atmospheric Pressure." By J. W. Lubbock, Esq., 

 F.R.S. 



* See our last volume, p. 377. 



f An abstract "of Dr. Dalton's Essay on the Constitution of the Atmo- 

 sphere will be found in Phil. Mag. First Series, vol. Ixviii. p. 310. 



X See our last volume, p. 380. 



2C2 



