24 Mr. W. S. Jevons on the Cirrous form of Cloud. 
Now a thread-like or stream-like appearance is nearly always 
to be seen, more or less, when two liquids of different densities 
are being mixed together, as in making ordinary chemical solu- 
tions, mixing alcohol and water, &c.; and if a drop of ink be 
added to a glass of clear water, it will be observed to sink down- 
wards into it in tape-like streams, and eventually to spread about 
in threads of a more or less czrrous character. 
This same appearance may be shown more or less distinctly in 
a multitude of different ways, but the following experiment has 
been devised and selected as presenting the mast complete and 
striking representation of a cirrous cloud ; and it was the acci- 
dental observation of appearances nearly the same as those pro- 
duced in this experiment which led me to form the present theory. 
Exp. 1. To about 800 grms. of pure water add 2 or 3 drops 
of hydrochloric acid, and 1 grm. measure of a strong solution of 
white sugar (spec. grav. of solution 115). Warm this to rather 
above 100° F., and pour the greater portion into an ordinary glass 
beaker about 5 inches in diameter and 9 or 10 in height (fig. 1). 
Fig. 1, 
a. Dises 0 
other stuffing. 
This beaker should be surrounded by a second larger one to pre- 
vent disturbance of temperature; and a tube-funnel, allowmg 
only a very slow stream to pass, must be placed in it reaching to 
the bottom, and with a termination like fig. 2; or with such 
similar contrivance as shall prevent all violent currents, and allow 
us to introduce further quantities of liquid without the least dis- 
turbance of the strata above. 
The remainder of the hot solution of sugar must be added by 
this funnel; and before this is quite run out, a little pure cold 
water is to be added so as to cleanse the apparatus. Then, 
again, without allowing the stream to break, a second different 
stratum must be added, previously prepared, and consisting of 
800 grins. of distilled water at the ordmary temperature of the 
