6 HISTORT of the SOCIETT. 



not feem a very material difFerence, when it is remembered, 

 that the inftant when any quantity attains either its greateft or 

 its leafl; (late is not eafily afcertained with precifion. From the 

 obfervations as detailed by M. La man on, the time of the mini- 

 mum feems to anfwer fully as well to 5 as to 4 ; fo that the dif- 

 ference of the refults is in every view inconfiderable, and their 

 coincidence, on the whole, not a little lingular. The variations 

 in Dr Balfour's barometer between the neareft maximum and 

 minimum^ is fometimes about tV th of an inch, though in general 

 confiderably lefs. 



In the abftrafl of Dr Balfour's obfervations referred to 

 above, it is remarked, that it feems not improbable that thefe va- 

 riations of the barometer are connedled with the reciprocations of 

 the fea and land winds during the day and night. But whatever 

 may have been formerly the probability of this fuppofition, it 

 is entirelv deftroyed by the obfervations px" the French navi- 

 gators. Thefe obfervations were made too far out at fea to 

 leave room for fuppofing that the land winds had any influence 

 on the phenomena to which they refer. It is at the fame time 

 doubtful, whether thofe phenomena can be afcribed to the atmo- 

 fpherical tides produced by the fun and moon, as the ebbing and 

 fiozuing of the mercury in the barometer appears to have no de- 

 pendence on the pofition of thofe luminaries relatively to one 

 another, but happens, it would feem, conftantly at the fame 

 hour, in ail afpefts of the moon and all feafons of the year. The 

 fubjedl is well deferving of a fuller inveftigation. We Ihould 

 probably before now have had farther information refpetfting 

 it, if happily the able navigator above named, and his brave af- 

 fociates, had been deflined to revifit their native fhores. The 

 cruel fate of an expedition fo well planned, and fo well appoint- 

 ed for the purpofes of fcience, will never ceafc to be matter of 

 fincere regret. 



An 



