480 



SCIENCE 



[Vol. LVI, No. 1452 



But Eudolf and Szirtes^- and Angenheister^' 

 liave since shown that the latter belong to a 

 branch of the first reflected waves. However, 

 Angenheister was able to follow the direct com- 

 pressional waves to about 145°, which is a great 

 achievement. Beyond this we have no proof 

 for their existence as yet. Hence it will be 

 seen how weak is the author's argument for a 

 viscous fluid state of the earth's core. If it is a 

 viscous fluid, the , longitudinal waves should be 

 transmitted and the transverse waves should 

 not. If it is an elastic solid, both ;the longitu- 

 dinal and the transverse waves should be able 

 to traverse it along some path, not necessarily 

 a straight one. Do they? Future investiga- 

 tion may tell us. For the present, modern 

 seismologists and geophysioists^'' suppose the 

 core of the earth to be a rigid solid. 



James B. Macelv^ane 

 University of California 



THE BEGINNING OF AMERICAN GEOLOGY 

 To THE Editor op Science: I have been 

 reading with very great pleasure Dr. J. M. 

 Clarke's interesting account of the beginnings 

 of Ameiican geology in his life of James Hall, 

 which has recently been published. 



On page 218 he refers to the statement that 

 Charles T. Jackson "drew a plan for the New 

 York Survey, a statement repeated in Apple- 

 ton's Cyclopedia of American Biography" but 

 concerning ■which he (Clarke) has "never seen 

 documentary evidence." 



Without in any way desiring to dispute Dr. 

 Clai'ke's contention it may be worth while to 

 say that the sketch in the Cyclopedia referred 

 to was written by me and that a proof of the 

 sketch received the approval of one member of 

 Jackson's famih'. The circumstances are quite 



12 E. Rudolf una S. Szirtes, Pliys. Zeitsohr., 

 August 1, 1914. 



13 Op. cit., pp. 11, 24, 27. 



Also: G. Angenheister: "A study of Pacific 

 Earthquakes," The New Zealand Journal of 

 Science and Technology, Vol. IV, No. 5, 1921, pp. 

 216-217, 224. 



1* Cfr. A. Sieberg : ' ' Auf bau und physikalische 

 Verhaltnisse des Erdkorpers unter besonderer 

 Beriieksichtigung der Erdrinde, ' ' Geologische 

 Bundschau, Band XII, Heft 6/8, 1922, pp. 346- 

 359. 



clear in my memory. Owing to Jackson's 

 death I did not know to whom to send the 

 proof until, telling my trouble to Henry Car- 

 rington Bolton, he called my attention to the 

 fact that Jackson's son or nephew had been 

 with him in the -class of '62 in Columbia. This 

 information resulted in my submitting the 

 sketch to some proper person who not only 

 approved the article but sent me a portrait 

 of Jackson showing him seated on a chair with 

 both hands on his knees extending outward 

 holding medals. 



It is possible that the item about the New 

 York Survey came from the younger Silliman's 

 masterly article on the "Contributions of 

 American Chemists" that he delivered at the 

 Centennial of Chemistry held in Northumber- 

 land in 1874, and which was published in the 

 American Chemist. If so, then the informa- 

 tion came to Silliman directly from Jackson. 



May I add for the information of students 

 of the history of chemistry in America that 

 Jackson received pupils in his laboratory in 

 Boston, just as Booth and Garrett did in Phila- 

 delphia, and that it was in his laboratory that 

 Charles A. Joy, who later held professorial 

 appointments in Union and Columbia, re- 

 ceived his early knowledge of chemistry before 

 going to Grottingen. 



Dr. Clarke persists in writing 0. M. Mitchel's 

 name with two I's. Mitchel was a very remark- 

 able man and like Jackson was conspicuous for 

 not being able to carry out the great things 

 that he had in his mind. He died of yellow 

 fever during the Civil War, and, while holding 

 important commands, so persistently pestered 

 Halleck with plans and recommendations to cut 

 the Confederacy in two that he was removed 

 and sent to Hilton Head. 



If Dr. Clarke should issue a second edition 

 of his valuable contribution to the history of 

 science, I would suggest that Newberry's con- 

 nection with the Sanitary Commission was 

 rather administrative than medical, as can be 

 seen by his printed report of 'which a digest 

 appears in the article on Newberry in the 

 "Cyclopedia of American Biography." 



The unfortunate experiences of many of the 

 early State surveys has been very fully told 

 by Merrill in his valuable "History of Ameri- 



