1 50 American Philosophical Society. 



All the country described by Mr. Murchison as superior to the Llan- 

 deilo flags, separated into three groups — upper, middle, and lower. 

 East of Berwyn chain, lower group. North of the Berwyn chain 

 (Denbighshire), upper, middle, and lower groups ; but with a new 

 mineral type, and without any upper bands of limestone. West- 

 moreland : upper group largely developed, and including fossils of the 

 tilestone ; middle group without limestone bands or fossils ; lower 

 group with many characteristic fossils. Horton and Ingleton, mid- 

 dle and upper groups. Ireland (Waterford and Kerry), lower group. 

 Scotland (Ayrshire), Silurian group, but not defined. 



4. Sub-Silurian, or Upper Cambrian. — The old rocks of South "Wales 

 below the preceding division ; containing Graptolites, but no well- 

 defined calcareous band, and very few fossils. A part of the Berwyn 

 chain based on the Bala limestone. The upper part of the roofing 

 slates, &c, of Cumberland, immediately under the Caradoc limestone 

 (of Coniston, &c). Slates of Charnwood Forest? Slates of the 

 Mourne mountains, of the Galloway chain, &c. 



5. Lower Cambrian. — The great slate group of North "Wales be- 

 low the Bala limestone. The old roofing slates of Cumberland. 



6. Lower Cumbrian, or Skiddaw slate. — Slates of Skiddaw Forest, 

 lower part metamorphic. Provisionally arranged in this place, the 

 chlorite slates, &c, of Anglesea and Caernarvonshire. 



AMERICAN PHILOSOPHICAL SOCIETY. 



January 21, 1842. — Dr.Hare made an oral communication respect- 

 ing a new aethereal liquid which he had succeeded in obtaining. 



He mentioned that he had procured, by means of hyponitrite of 

 soda, diluted sulphuric acid and pyroxylic spirit, an aethereal liquid, 

 in which methyl (C 3 H 3 ) might be inferred to perform the same part 

 as aethyl (C 4 H 5 ) in hyponitrous aether. In fact, by substituting py- 

 roxylic spirit for alcohol, this new aether was elaborated by the pro- 

 cess for hyponitrous aether, of which he had published an account in 

 the Society's Transactions, vol. vii. part 2. 



The compound which was the subject of his communication had a 

 great resemblance to alcoholic hyponitrous aether, similarly evolved, 

 in colour, smell and taste, although there was still a difference suffi- 

 cient to prevent the one from being mistaken for the other. 



Pyroxylic spirit appeared to have a greater disposition than alcohol 

 to combine with the aether generated from it, probably in consequence 

 of its having less affinity for water. The boiling point appeared to 

 be nearly the same in both of the aethers ; and in both, in consequence 

 of the escape of an aethereal gas, an effervescence, resembling that of 

 ebullition, was observed to take place at a lower temperature than 

 that at which the boiling point became stationary. The aethereal gas, 

 of which Dr. Hare had given an account in his communication re- 

 specting hyponitrous aether, seemed to have escaped the attention of 

 European chemists; and, even after it had been noticed by him, 

 seemed to be overlooked by Liebig, Kane, and others, in their subse- 

 quent publications. 



Dr. Hare attached the more importance to his success in producing 



