334 The American Geologist. May, 1892 
discover if there is any connection between the retreat of glaciers 
and recorded observations on climatic changes, it would appear 
that an inspection of the records of mean annual temperature 
and mean annual rainfall, without discussing the causes of these 
changes, would be sufficient. Difficulty in the way of making 
this comparison arises, however, from the fact that in the glacial 
records we have only the general result of a long series of changes, 
all minor features of which are lost; while in the weather records 
sufficient time has not been covered by the observations to show 
secular changes a century or more in extent, which would be 
necessary to reach a satisfactory conclusion. The weather records 
on the Pacific coast did not begin until 1849, and were not made 
at a sufficient number of stations to furnish a basis for determin- 
ing general climatic changes until a number of years later. This 
lack of observations render it impossible to make the comparison 
desired. The same proves to be true also on attempting to cor- 
_relate the retreat of the glaciers with the weather records of the 
entire North American continent. The only conclusion to be 
reached in this connection seems to be that the data relating to 
both the fluctuations of glaciers and to climatic changes are inad- 
equate for satisfactory comparison. . 
Curves showing secular changes in temperature and rainfall of 
the world for more than one hundred years, derived from all 
available weather records, have been published by Dr. Bruckner, * 
of the University of Berne. The observations of temperature 
embrace the period between 1730 and 1885 and show a gradual 
rise during the latter part of this interval. The curve indicating 
rainfall includes the period between 1775 and 1885, and shows a 
gradual decrease towards the end of this period. These results 
seem in harmony with the decrease of the glaciers of Europe and 
Asia and of the west coast of North America, but how accurately 
the curves indicate actual changes in the elements of climate re- 
ferred to it is impossible to say. The general rise in the tempera- 
ture curve, the gradual fall in the curve representing precipitation, 
towards the end of the periods of observation are probably in- 
fluenced by the varying character of the observations during 
different portions of the period. The correspondence between 
the general retreat of the glaciers in the northern hemisphere and 
the changes in the records of temperature and rainfall referred to 
*Penk’s Geog. Ablandlunger, Vol. 1v, 1890, p. 329. 
