Royal Irish Academy. 591 



about daylight, when it will be at rest, and the barometer will again 

 be at a mean. 



" This theory was given by me to the Journal of the Franklin 

 Institute, and published ten or twelve years ago. 



" I ventured in that paper to predict, notwithstanding some al- 

 leged observations at St. Bernard's Hospital to the contrary, that it 

 would be found by more careful observations that the morning maxi- 

 mum fluctuation would be greater in lofty situations, on the sides of 

 mountains, provided they were not very lofty, than on the plain below. 



" For it is manifest, that there will be not only a reaction at these 

 lofty situations, (a little less, it is true, than below,) but some of the 

 air will be lifted up, by the expansion of the air below, above the 

 upper place of observation ; which would in all probability more 

 than compensate the diminished reaction at moderate elevations. 



" This prediction has been entirely verified by Lieutenant-Colonel 

 Sykes's observations in India, and this verification may be consi- 

 dered as a strong proof of the correctness of the theory. It is quite 

 probable, that maximum day fluctuation occurs later at considerable 

 elevations than on the plain below. 



" The theory would lead us also to suppose, that at very great 

 elevations, where the reaction is very minute, only two fluctuations 

 would be found in the day : the maximum at about two o'clock p.m., 

 when most air would be above the barometer ; and the minimum at 

 daylight in the morning, when least air would be above it ; but I 

 know of no observations to confirm or refute these deductions." 



Mr. Ball brought under the notice of the Academy the fact, that 

 the ordinary Sturgeon of the Dublin markets is an undescribed species. 

 He stated that Mr. Thompson of Belfast, and Professor Agassiz, con- 

 curred with him in this opinion, and he proposed to call it Accipen- 

 ser Thompsoni, purposing, if permitted, to give figures and full de- 

 scriptions in a future number of the ' Proceedings.' 



The Archbishop of Dublin made some observations on a remark- 

 able meteor, lately seen in different parts of Britain. 



December 14. — Dr. Apjohn read the following notice, by George 

 J. Knox, Esq., of " some Improvements in the Voltaic Pile." 



" The chief imperfection in the voltaic pile — its want of a constant 

 uniform power of long duration, by which it is rendered almost use- 

 less as an instrument of research — having been overcome by the 

 ability of Professor Daniell, the only thing that remained to render it 

 efficient seemed to be, to increase its power ; a desideratum accom- 

 plished by Mr. Grove, by substituting for copper and sulphate of 

 copper, platinum and nitric acid. 



" The following experiments were undertaken with the intention 

 of estimating the relative values of the different constructions of 

 Grove's battery, recommended by Mr. Knight of Foster Lane, as far 

 as respects the arrangement of the zinc and platina plates, when, to 

 my surprise, I found the same quantity of electricity to be evolved 

 when the zinc is bent so as to expose an opposing surface to each 

 surface of a platinum plate, as when a platinum plate, of the size of 

 the former zinc, is similarly placed with respect to a plate of zinc of 



