194 Mr. Armstrong's Account of a 



of which are now confined to the Old World, with others, 

 which not only appear to have been peculiar to America, but 

 the living analogues of which are also now confined to that 

 continent, forms a very interesting and important subject of 

 investigation in palaeontological geography. See Dr. Buck- 

 land's memoir " On the occurrence of the remains of Ele- 

 phants," &c. " in Eschscholtz Bay," forming part of the Ap- 

 pendix to Capt. F. W. Beechey's " Narrative of a Voyage to 

 the Pacific and Beering's Strait performed in H.M.S. Blossom 

 in the years 1825, 1826, 1827, 1828," pp.593, 597; and a paper 

 supplementary to Dr. Buckland's memoir, by E. W. Brayley, 

 Jun., on the " Organic Remains in the Diluvium of the Arctic 

 Circle, and on the 'probability that one of the Fossil Bones 

 brought from Eschscholtz Bay belonged to a species of Mega- 

 therium" inserted in Phil. Mag. S. 2. vol. ix. pp. 4-11, 416. 

 The vertebra in question, it appears from Dr. Buckland's me- 

 moir, was included in the series of specimens selected from 

 the Eschscholtz Bay fossils for the British Museum. It may 

 tend to abbreviate the labours of future inquirers on the sub- 

 ject, to add that it is not alluded to, either in Mr. Clift's account 

 of the remains of the Megatherium sent from Buenos Ayres 

 by Sir Woodbine Parish, Trans. Geol. Soc. S. 2. vol. iii. p. 

 437 ; or in Professor Owen's elaborate work on the Mylodon 

 robustus and Megatherioid Quadrupeds in general. Nor is 

 it mentioned by Dr. Buckland in his Bridgewater Treatise, 

 although he notices (vol. i. p. 142 note) the apparent exten- 

 sion of the Megatherium "north of the equator as far as the 

 United States," instancing some former observations of the 

 occurrence of its bones and teeth in Georgia. — E. W. B.] 



XXV. Account of a Hydro-electric Machine constructed for 

 the Polytechnic Institution, and of some Experiments per- 

 formed by its means. By W. G. Armstrong, Esq.* 

 To Michael Faraday, Esq., fyc. fyc. fyc. 

 Dear Sir, 



THE following account of an electric boiler, which has 

 been recently constructed under my superintendence, 

 and of certain experiments which have been made with it, is 

 addressed to you, not only because you have lately investi- 

 gated with your usual ability and success the subject of steam 

 electricity, but because the results of the experiments which I 

 am about to describe are calculated to elucidate and establish 

 some of your views respecting the nature and identity of the 

 various species of electricity. 



* Communicated by Dr. Faraday, an abstract of whose paper alluded to 

 by the Author will be found in Phil. Mag. S. 3. vol. xx. p. 486. 



