260 Prof. Forbes on Terrestrial Magnetic Intensity. 



fiving the same mean result to four decimal places. Professor 

 lansteen has given *8428, which must be considered as a 

 close coincidence.* 



For Brussels I find by "No. I." 0-960 



by "Flat," 0*965 



Captain Sabine 0*951 



M. Quetelet (4 series) 0*964 



M. Rudberg 0*971 



I subjoin a few comparisons of stations common to M. Que- 

 telet's seriest and mine. 



Quetelet. Forbes, No. 1. 



Castle of Heidelberg 1*020 \ 



Town of do 1*024 J I '° ' 



Konigstuhl (summit) 1*027 1*018 



Geneva 1*080 1*076 



Chamouni 1*093 1*085 



St. Bernard 1*097 1*082 



Martigny 1*092 l*08'i 



[To be continued.] 



XXX. On a New Rain Gauge. By the Rev. Thomas Knox, 



M.R.LA.% 



[With a Figure : Plate II.] 

 f~\ N the 26th of June last, a new rain-gauge was exhibited 

 r*7 to the Royal Irish Academy, contrived by the Rev. Tho- 

 mas Knox. 



The object of this instrument is to register the amount of 

 rain that falls when the wind is in different points. Its con- 

 struction is very simple. The water, — instead of descending 

 from the reservoir directly into the tube of registry, — passes 

 through a lateral tube into an annular-shaped vessel, divided 

 into eight compartments, each of which terminates below in a 

 graduated glass tube. It is obvious, then, that if the eight 

 tubes be set to correspond with the cardinal and intermediate 

 points, and that the reservoir be made to revolve on a vertical 

 axis by means of a vane, the direction of which corresponds 

 with that of the lateral tube, the object proposed will be attain- 

 ed. Mr. Knox has preferred to make the reservoir fixed, and 

 the system of tubes moveable ; but the result is obviously the 

 same. 



* Since this paper was read, this result has been still more nearly con- 

 firmed by the observations of Professor Bache of Philadelphia, who, by 

 connecting Edinburgh and Dublin, and taking Professor Lloyd and Captain 

 Sabine's observations for the comparative intensities at Dublin and Paris, 

 has obtained the number *8400. 



f See his two papers in the Me moires de V Academie de Bruxelles, tome 

 iv. ; and an abstract in the Annuaire de V Observatoire de Bruxelles, 1834. 



% From the Proceedings of the Royal Irish Academy, No. 5. 



