1880 .] 
53 
[Nichols. 
he gathered, prepared, and arranged, doubtless the most complete 
and most beautiful collection of North American coleoptera in this 
country and probably in the world. Acquainted intimately with 
him, as I was for many years, I take pleasure in testifying to his 
excellent and upright character as a man, and to his exemplary 
enthusiasm in one of the branches of study for the furtherance of 
which this Society was established. Mr. Smith died in Cam- 
bridge, of heart disease, July 6th, 1880, in the forty-seventh year 
of his age. John Orne, Jr. 
The following paper was read : 
ON THE TEMPERATURE OF FRESH-WATER PONDS AND 
LAKES. 
BY WM. RIPLEY NICHOLS. 
Sometime since I had reasons for wishing to know the facts 
with reference to the temperature, at different depths, and at dif- 
ferent seasons, of the rather shallow fresh- water ponds and lakes 
such as are used in this part of the country as sources of water- 
supply. I was not at that time able to find any series of observa- 
tions which answered my purpose, and was, consequently, led to 
make some observations on the ponds in this neighborhood. 
I was also led to search rather carefully for what might have 
already been published on the general subject of the temperature 
of ponds and lakes. I shall append to this communication a list 
of such published papers as I have been able to meet with, but 
these, in most instances, are the results of isolated or rather infre- 
quent observations, or, if there is a daily record, it is almost inva- 
variably of the surface water alone. Besides that which has been 
published, I am aware that observations are made in various cities 
and towns on the water used for the general supply, sometimes 
at its source, sometimes as it issues from the conduit, and some- 
times in the pump-well of the water-works. These observations, 
if published at all, appear in local reports not readily accessible, 
and they are, indeed, seldom published in detail. 
