Geology and Natural History. 79 



would all liquefy under the action of pressure. He even imag- 

 ines that I have drawn this conclusion from my own experiments ! 

 To second his statement he alters some passages of my works, 

 substituting for the word "welding" (souder) while I have used 

 that of "fusion,'''' or even in misconstruing the text. The reader 

 may judge : Mr. Hallock makes me state, for instance (p. 281), 

 " Sulphur prismatic — 5000 atm. -fusion to the octahedral form . ." 

 he adds, of his own invention : "and so on through a long and 

 varied list." But I said*, on page 391 of my memoir of 1880 : 

 " Du soufre prismatique transparent, fraichement prepare, a 'et'e 

 sousmis d une pi°ession de 5000 atm. d la temperature de 13° ; il 

 s'est mottle en un bloc opaque beaucoup plus dur que ceux qu'on 



obtient par fusion." ! After having thus prepared the 



ground, he gives an account of some new experiments which have 

 shown him, naturally, that solid bodies do not fuse under pressure ! 

 Finally, he closes by showing my absurdity, referring to Ama- 

 gat's experiments which prove, as I have just called to mind, 

 the solidification of certain liquids by pressure, that which ex- 

 cludes the contrary. It is quite evident that there is no reason 

 for arguing with Mr. Hallock, since his study, which rests on a 

 chimera, is, in my opinion, null and void. But I think I have a 

 right to protest against the carelessness which has led him thus to 

 misstate my views. 

 Liege, 6 Nov. 188*7. 



12. Lessons in Elementary Practical Physics : vol. ii, Electri- 

 city and Magnetism; by Balfour Stewart and W. W. Hal- 

 dane Gke. 497 pp. 12mo. London and New York, 1887 (Mac- 

 millan & Co.). — Those who are already familiar with the preced- 

 ing part of this excellent work on Practical Physics will not need 

 any special introduction to this second volume. It covers the 

 subjects of electricity and magnetism, the first three chapters 

 giving the elementary phenomena and principles to be worked 

 through by the student experimentally; after this he is fitted to 

 take up the more advanced portion dealing in successive chapters 

 with the measurement of resistance, the tangent galvanometer, 

 the determination of the magnetic elements, electro-magnetism, 

 the condenser, electrometer and so on. 



II. Geology and Natukal Histoey. 



1. Communication by Raphael Pumpelly, of the IT. S. Geo- 

 logical Survey, on the fossils of Littleton, New Hampshire. — In 

 the course of a reconnaissance of some of the limestone areas of 

 New England made under my direction by Mr. T. Nelson Dale 

 in August and September, 1885, the following fossils were found 

 in the limestone and interbedded slates at Fitch Hill, the north 

 end of Blueberry or Parker Mountain, near Littleton, N. H. 



The determinations of the trilobites and mollusks were made 

 by Mr. Chas. D. Walcott, those of the corals by Mr. C. Rominger. 

 Dalmanites limulurus (Green), abundant ; Strophomena rhom- 



