202 The Aiiicr'ican (n'ologisf. Miirch, i89a 
gravel ut iMilfonl. in tlu' Little Miami A-alley. (2) It would ex- 
plain the Ked Mank and the Ludlow Grove deposits in the Madi- 
sonvillc valley. {'X) It would explain the deposit of till and 
gravel opposite and below Mill creek valley. (4) It would explain 
the deposit at the mouth of the Big Miami valley; and (5) it 
would, as the ice receded northward, account for the accumula- 
tion of drift near Hamilton. Of course, when the Ohio attempted . 
to return to what was evidently its old channel, by way of Red 
Hank and Ludlow (h'ove on the one hand, and Mill creek on the 
other, it would find the way blocked; and it would then have to 
cut for itself a new course. This it has done past the mouth of 
Mill creek. Looking, therefore, at the facts as seen at and a))out 
Cincinnati, the theory of an ice-dam does not seem untenaljle. In 
fact, it is almost a necessity. It may not have performed all the 
work that has lieen credited to it, audits existence may have been 
long or short. This can possilily be measured by the extent of 
the deposits mentioned. All of these merit and recpiire more ex- 
tended study. 
The C.vrsE of ax Lk Aok. — Ball. 
J. F. Blake, in Annuls of Brili.tli Oeoliifjy, IHSH, p. 14:i. 
The name of the writer of this book is sufficient to secure great 
attention to what he says — but, when to follow him involves the 
imputation of a fundamental error to Herscheland of gross igno- 
rance to all other writers on the subject, we must pause. If the 
words of Sir John Herschel had the meaning which the author 
assigns to them, they would lead to the conclusion that the author 
draws from them, — and ;irithmetically works out so that there can 
be no mistake, — that the only ditfeience between summer and 
winter temperature is that due to the concentration of etiual quan- 
tities of heat into une([ual periods of time. But it would have 
this further result that in the hemisphere which has a long sum- 
mer and a short winter the summer would actually be the colder. 
We cannot possibly believe that Herschel and his followers could 
not perceive this result. It is perfectly clear that the heat spoken of 
by Herschel is the ' -supply" from the sun, and is supposed through • 
out to be received on an ecpuil area equally inclined to the sun's 
rays. The phenomena of summer and winter depend, of course, 
on something else altogether, namely, the oblicjuity of the surface 
