METHODS OF CALCULATING TIIE HYDROMETRIC DATA. 33
In employing method I the sections were plotted on a very large scale on cross-ruled paper and the curves of the river-bottom put in by hand; then the areas were measured by a polar planimeter, made by F. J. Berg of Stockholm, and belonging to the .Mechanical Institute of the University of Stockholm.
As will be seen, there is a very close agreement between the results obtained by the two methods in the first three out of our four examples, in which the soundings occur close together; and in the fourth case, in which the distances between the soundings are greater, the agreement may be pronounced satisfactory. Whence we conclude, that the simpler method II is sufficiently exact for all cases.
Dr. Nils Ekholm.
IIIF Color HighRes
