REVIEWS 79 
the paper with an invitation to suggest points of revision or to add a statement to 
go with it. In response to this, the following comments have been prepared by 
Mr. Hayford. In the light of these, the review might well be modified at some points, 
but to avoid disturbing the basis of Mr. Hayford’s comments it is left precisely as 
submitted:—T. €- C: 
COMMENT ON THE ABOVE REVIEW BY MR. JOHN F. HAYFORD 
The Report reviewed on the preceding pages by Professor Chamberlin, 
is essentially a preliminary statement. It was necessarily short, being 
one of many presented by various countries to the International Geodetic 
Association for publication in its triennial report. Another short pre- 
liminary statement in regard to the same investigation is also available 
in print, in the Proceedings of the Washington Academy of Sciences. Both 
of these statements are subject to defects due to brevity. So, also, must 
the statement here made be brief and defective. It is hoped that a much 
more complete statement of the investigation may be published by the 
Coast and Geodetic Survey within a year from date. 
The fair and clear review by Professor Chamberlin is welcomed by 
the undersigned. A few statements seem to be necessary, in justice to 
the geodetic investigation under discussion, in order that there may be 
no misunderstanding. : 
Professor Chamberlin’s distinction between demonstration and inter- 
pretation, in connection with this investigation, is correct. _The investi- 
gation demonstrates that the present distribution of densities follows a 
certain law. The statement of the meaning of this law in terms of rigidity 
is interpretation, and this interpretation depends, in part, on considera- 
tions outside the scope of the geodetic investigation. It seems to the 
writer, however, that the interpretation, given in terms of rigidity, is 
reasonably safe. When the interrelations of the geodetic and geologic 
evidence are more fully appreciated than at present, it is believed that 
others will reach the same conclusion. 
Before discussing isostasy, it is necessary to get a clear conception of 
what the word means. It is stated in the review that certain language 
in the Report ‘carries the impression of a positive affirmation of liquidity 
or viscousness at the base of the crust in which the differentiated densities 
reside. Such is the usual conception that goes with the term ‘isostasy,’ 
t John F, Hayford, C.E., “The Geodetic Evidence of Isostasy, with a Considera- 
tion of the Depth and Completeness of the Isostatic Compensation and of the Bearing 
of the Evidence upon Some of the Greater Problems of Geology,”’ Proc. Wash. Acad. 
Sci., Vol. VIII, pp. 25-40 (May, 1906). The writer will be glad to furnish copies of 
this paper to interested persons. 
