( xxxi ) 



charged with the hydrogenium and rises to the surface, there to dis- 

 charge the gas, it then siaks until it again touches the metal and 

 again rises. If the platinum shots are used, they remain in contact 

 with the dissolving metal, and this intermittent action does not take 

 place. 



On Fluorescence as a means of Detecting Adidteration. 



If an adulterant is fluorescent, and the adulterated substance is 

 non-fluorescent, we have a ready and most delicate method of proving 

 the adulteration. As a familiar example, the adulteration of miistard 

 with tunneric is given. Turmeric yellow is fluorescent, but mustard 

 yellow is non-fluorescent. The fluorescent phenomenon is more deli- 

 cate than the chemical tests would be. In all cases, however, it is 

 necessary that the non-fluorescence of the substance subject to 

 adulteration should be proved as detailed in the note. 



On the Printing Inks of the l6th and IJth Centuries. 



The object of this note is to point out that although from the time 

 of Johann Faust, printing inks consisted of carbon with some vehicle by 

 which the carbon is bound to the surface of the paper, yet this vehicle 

 previous to 1 700, is very soluble in dilute alkalies. Specimens of 

 printing when placed in dilute ammonia instantly float off the 

 surface, but inks after this date are rarely altered. This peculiarity 

 is not confiaed to one country, but from the specimens of printing 

 tried would appear to be very general. 



[This paper appears in the Proceedings, Series II., Yol. II., 

 Science, Part L] 



Itr, G. E. Leeper read a paper " On Ptetro-Peritoneal Cavities in 

 ITan." 



[This paper appears in the Proceedings, Series II., Yol. II., 

 Science, Part I, Plate 5.] 



The Treasurer exhibited an impression of a bronze mould found at 

 Lough Pea, Carrickmacross, and read the following : — 



" Extract from Letter to J. R. Garstin, LL. B. 



"Loi-GH Fea, Cakeickmacross", 

 "1th December, 1874. 

 •' There has been lately found in the cave here under some moss 

 among the rocks a bronze mould, which I think is quite unique. It 



