REVIEWS 545 
North Carolina Geological Survey. J. A. HoimEs, State Geologist, 
Bull. 13; Clay Deposits and Clay Industry in North Caro- 
lina, by HernricuH ReEIs. 
There are few things more noticeable and at the same time more 
gratifying in the recent work of the state geological surveys than the 
increased attention paid to the economic and industrial portion of the 
work. So long as it remains necessary to justify the existence of sur- 
veys to appropriation committees, it will remain pleasant to point to 
practical work and direct economic returns in neighboring states. It 
has been abundantly shown that legislators do not usually object to 
paying for a reasonable amount of purely scientific investigation, pro- 
vided only that the practical work waiting to be done be not slighted. 
It is equally well demonstrated that it is only by conducting work 
along lines of both pure and applied science that state surveys attain 
their highest usefulness. They do better work and gain more quickly 
and hold more securely the confidence of those who pay for this work. 
Neglect of these truisms has led to the premature cutting off of more 
than one survey. It is pleasant, accordingly, to note that the reports 
coming from North Carolina are not only scientific in their accuracy, 
but practical in their scope. Such a paper as the one under review, 
by stimulating the development, and, in a sense, advertising the clay 
resources of the state, must inevitably be followed by direct material 
benefits. The care taken by the author to suggest changes and 
improvements in present treatment as well as to note lines of expan- 
sion, in view of his wide experience with clays, are exceedingly valu- 
able. 
The paper opens with a brief statement of the origin of clays, and 
a classification of those developed in North Carolina. ‘This is followed 
by a clear, though condensed, discussion of the chemical and physical 
properties of clays and of the geography and geology of the North 
Carolina deposits. The kaolin or china clays, pottery clays, fire clays, 
pipe clays, and brick clays are then discussed briefly with reference to 
distribution, character and proper treatment. A large number of 
analyses and tests have been made, and are not only inserted, but are 
interpreted. To persons outside the state the chapter devoted to the 
kaolins will naturally attract the most attention, since it is kaolin from 
North Carolina which figures so largely in the pottery industry of the 
whole country. Judging from certain facts brought out in the report 
the time may come when the kaolin will be extensively used in its 
