SEPARATING COLLOIDS FROM CRYSTALLOIDS BY FILTRATION. 147 
tinued to fly steadily. It is this remarkable stability that makes 
the cellular form of aeroplane so suitable for flying-machines, and 
it is a matter of surprise to the writer that other experimenters 
do not adopt it, especially as there is no charge for its use. 
For man lifting purposes, small kites are better than large ones. 
For instance, a nineteen square feet kite has been made that weighs 
nineteen ounces, and folds to about the size of an umbrella; ten 
of these could be tucked under one’s arm, and with a coil of line 
and a decent breeze an ascent could be made from the bridge of 
a torpedo boat or the top of an omnibus. 
Some confusion has arisen through the apparent ambiguity of 
the definitions of the dimensions of cellular kites. They fly at 
such a high angle and present such a small projected area to the 
wind, that when viewed from below, misunderstanding cannot 
ensue if :— ; 
Length equals the dimension in the direction the wind is blowing. 
Breadth equals the dimension horizontally at right angles to the 
length, 
Depth equals the dimension vertically at right angles to the length. 
Nore ox A METHOD or SEPARATING COLLOIDS From 
CRYSTALLOIDS sy FILTRATION. 
By C. J. Marvy, psc. u.B., Demonstrator of Physiology in the 
University of Sydney. 
(From the Physiological Laboratory of the University.) 
(Read before the Royal Society of N. S. Wales, August 5, 1896.] \ 
Tux method consists in filtering under a pressure of forty to fifty 
atmospheres, through a film of gelatin or gelatinous silicic acid. 
In order to do this the film must be supported at frequent intervals, 
