30 
DR. A. WALLER’S MICROSCOPIC OBSERVATIONS. 
Creosote condenses the breath, which agglomerates into globules apparent to the 
naked eye and long remains unaltered. 
Olive oil . — The globules are very minute and agglomerate slowly. The surface 
assumes a lacerated appearance, and the molecular dispersion appears simultaneously 
over the entire field of vision. Croton oil condenses a film reflecting the various 
spectral colours. 
Castor oil . — The condensed particles of water present the same appearance to the 
naked eye, or when assisted by the microscope, as the two preceding. If, before the 
globules have disappeared, they are covered over with another slip of glass having a 
film of oil previously placed on it, they are retained for a much longer period than 
if the surface of the glass had been perfectly dry. Almost all of them are adherent 
together, as in fig. 6, but without agglomerating into one. In some instances a larger 
globule, like a central nucleus, is seen covered with others adhering to it. Their ap- 
pearance reminds one strongly of the manner in which the condensed vapours of 
sulphur are found adhering together. 
Another means of subjecting particles of water to microscopic observation, con- 
sists in fixing them upon minute filaments, such as those of the spider’s web. I have 
found it most convenient to employ the filaments which contain the ova of the spider, 
or those of the cocoon of the silk-worm. Thin bundles of either of these exposed to 
steam from boiling water, were found after a few moments to have very minute 
globules condensed upon them, mostly imperceptible to the naked eye, about the 
same size as those obtained in Canada balsam from boiling water. These particles 
of water were all liquid globules without any signs of vesicular structure. In foggy 
weather the filaments of the spider’s web generally become covered with small 
globules of water, which in some cases are so minute as to give the filament a grey 
whitish aspect, like globules floating in the air, or in spirit of turpentine. These 
filaments, fixed between two small frames pressed close together, may be examined 
under the microscope. They are then seen covered with globules of water, and 
with others of an organic nature secreted by the spider. The former may readily be 
distinguished, by their quick evaporation, from the others which are permanent. 
The globules of water were about 0 , 02 mm . 
We may therefore conclude from the foregoing observations, that the term vesicular 
structure of globules, which was first proposed at a time when the knowledge of 
gaseous bodies was still in its infancy, has been adopted without sufficient foundation ; 
that the experiments on which it was grounded were unsatisfactory and imperfect ; 
and that whenever we are enabled to inspect the minutest particles of water arising 
from condensed steam or vapour, they consist of minute liquid globules without any 
appearance of internal cavity. 
Kensington, April 12 th, 1846. 
