Revieiv of Rece/it Geological Literature. i8i 
cent, usually about one-third of one per cent in granites, varies from 
almost nothing to 13 per cent in the limestones and dolomytes, and 
from 3 per cent to over 25 per cent in the sandstones. The author 
emphasizes his belief that the size of the pores is more important than 
the volume in determining damage by freezing and thawing, and cer- 
tainly the results of the freezing and thawing tests are somewhat er- 
ratic. Occasionally the frozen and thawed sample appears even 
stronger. The author feels safe in concluding that the loss of strength 
is greater in granite than sandstone, and is greater (absolutely) the 
greater the original strength. 
Tests for the action of SO.-; and CO2 were not very significant. 
Tests for the effect of high temperature showed that all the sand- 
stones and granites and some of the limestones had a more brick-like 
ring. As the temperature increased the planes of stratification became 
more distinct. 
The limestones were not injured by heating until calcination at 
1000° to I200°F. Sudden cooling caused the cubes to shed tlieir 
corners and occasionally after a while to crumble to pieces. 
The granites, especially, of course, decrepitated vigorously, wliilc 
the sandstones though apparently uninjured had lost almost all their 
coherence. 
Part III, pp. 429 to 456, is a brief, popular description of the min- 
erals and rocks referred to. The author has not entirely succeeded in 
keeping out terms like granolitic and ophitic which undefined will lie 
hardly intelligible to the readers to whom it is addressed. But this is a 
sin to which we arq all prone. Emphasis is laid on the importance of 
silica and unimportance of iron oxide as cements for sandstones. 
Greenstone is used in much the same way as Rutley in his "Gran- 
ites and Greenstones." 
Plate 49 gives a map of the jointing in different parts of Wiscon- 
sin. 
From p. 461 to p. 500 is the description of the plates, which illus- 
trate the results of the tests on the cubes, and 'a series of microphoto- 
graphs. Many of the latter are quite good and illustrate the desired 
features well, but in some the- inevitable limitations of the half tone 
process are all too conspicuous. 
We cannot leave this very valuable report without an expression 
of regret that one which besides matter of temporary value contains 
so much of permanent interest, and so many illustrations, some of those 
of polished rock surfaces being up to high water mark, should be 
printed on a cheap soft thick paper (probably not over 4 cent), which 
swells it to inordinate thickness, puts a strain on the cloth liindinir 
which will soon break its back, and will in a few years be so yellow and 
brittle that it can hardly be handled without injury. 
The plate paper is much better. A. c. L. 
