GEOLOGY AND NATURAL HISTORY. 4S5 



possible. After the lapse of about three months, (April 18 to July 14 J portions 

 were taken from each end of the tube, and from the connecting piece below, (a 

 small orifice being made in this ;) and the amount of salt in each portion "was 

 accurately determined. Now, if the principle of diffusion had not b< j en brought 

 into play, it is evident that the solution in the open limb of the tube ought to have 

 been stronger than that in the closed limb, although, by the circulating process, 

 the amount of salt at the top and bottom of the former might have been alike ; 

 and, again, it will be equally evident that if the principle of diffusiou were brought 

 into play, the supposed sinking of the surface solution, as the result of evapora- 

 tion, must be altogether imaginary. Six separate determinations, two from each 

 of the three portions of the tube, shewed a per centage of salt, essentially the 

 same. The following table exhibits the results obtained: 



Solution. Am. of Salt. Per ct'ge 

 of salt. 



( A. From the top of the open limb 302.26-1.. 11.59... 3.830 



1 4 B. From the bottom of the same 300.24... 11.51... 3.835 



( C. From the top of the closed limb 288.60... 11.055.. 3.831 



! A. From the top of the open limb 264.83... 10.16... 3.837 



B. From the bottom of the same 290.10... 11.12... 3.833 



C. From the top of the closed limb 306.66... 11.1b... 3.832 



These experiments justify us, I ihink, in assuming that owing to diffusion, the 

 surface waters of the sea do not become heavier than the lower strata simply by 

 losing water by evaporation. It is quite true, that under the influence of evapor- 

 ation a lowering of temperature may take place, and that an upward and down- 

 ward circulation, to a certain extent, may in this manner be produced* ; but the 

 same reasoning will apply, and with equal force, to bodies of fresh water. In con- 

 clusion, therefore, I feel justified in expressing my sustained belief, ihntthe theory 

 which I have proposed to account for the saltness <~f the sea, is worthy of ac- 

 ceptance ; this theory being that the sea is salt, essentially if not principally, in 

 order to regulate evaporation. 



Note. — Through the courtesy of various members of the American Association 

 for the Advancement of Science, we have been favoured with abstracts of their 

 papers, authenticated and revised reports, or, in. some cases, with the loan of the 

 original papers as submitted to the meeting in the different sections. We shall 

 accordingly continue our report of the Montreal meeting in the next number, and 

 endeavour to furnish a succinct embodiment of some of the most important con- 

 tributions to science, presented at the first American Scientific Congress held 

 within our Canadian frontier. 



The January number of the Journal will also contain such a selection as our 

 limited space will allow, from the numerous and valuable communications laid 

 before the various sections during the recent meeting of the British Association 

 for the Advancement of Science, at Dublin. 



* It should be stated that no intermixture could have taken place in the closed limb of 

 the apparatus described above by ascending currents produced by unequal temperature, as 

 the temperature of the lower portion of the closed tube was kept purposely lower (or at least 

 prevented from becoming higher) than the upper portion by means of a damp rag perma- 

 nently attached to it. 



