Intelligence and Miscellaneous Articles. 147 



lying conformably on the Upper Silurian. Beds, as seen in the coast 

 of the Dingle promontory and overlain unconformably by either Old 

 Red Sandstone or Lower Carboniferous beds, 10,000 to 12,000 feet. 

 North. — " The Pintona Beds," occupying large tracts of London- 

 derry, ALonaghan, and Tyrone, resting unconformably on the Lower 

 Silurian beds of Pomeroy, and overlain unconformably by the Old 

 Bed Sandstone or Lower Carboniferous beds, 5000 to 6000 feet in 

 thickness. 



Scotland. 



Beds of the so-called " Lower Old Bed Sandstone," with fish and 

 crustaceans, included in Professor Geikie's " Lake Orcadie, Lake 

 Caledonia, and Lake Cheviot," underlying unconformably the Old 

 Bed Sandstone and Lower Calciferous Sandstone, and resting un- 

 conformable on older crystalline rocks. Thickness in Caithness 

 about 16,200 feet. 



The author considered that all these beds were representative of 

 one another in time, deposited under lacustrine or estuarine con- 

 ditions, and, as their name indicated, forming a great group inter- 

 mediate between the Silurian on the one hand and the Devonian 

 on the other. He also submitted that their importance, as indicated 

 by their great development in Ireland and Scotland, entitled them 

 to a distinctive name such as that proposed. 



XVII. Intelligence and Miscellaneous Articles. 



ON THE LUMINOUS INTENSITIES OF THE RADIATIONS EMITTED 

 BY INCANDESCENT PLATINUM. RT PROF. J. YIOLLE. 



T HATE measured at different temperatures, and for various ra- 

 -*- diations, the light-intensities of incandescent platinum. 



I have selected as temperatures some of the melting-points 

 which I previously determined in degrees of the air-thermometer, 

 and which I here repeat (correcting the melting-point of gold, 

 which was set down by mistake at 1035°) : — 



o 



Melting-point of silver 954 



gold 1045 



„ „ palladium 1500 



„ „ platinum 1775 



In order to get some platinum, for example, at 1045°, a button 

 of platinum of about 200 grams weight was put into a crucible of 

 unglazed porcelain, which was introduced into a second crucible, 

 made of fireclay, and already containing at its lower part 500 grams 

 of gold. The whole was placed in a large vertical Perrot furnace 

 traversed along its axis by a long fireclay tube, through which the 

 surface of the platinum could be seen. It was heated up to the 

 fusion of the gold ; the arrival gas-cock was then, to a slight extent, 



