46 Mr. William Ingrams. 
other skeletons, but these diatomaceous skeletons—what of 
them, their envelopes, their contained parts? How could one 
supply them so as to be able to form an adequate conception of 
the perfect forms? The guano supplied, and will supply all who 
will take the trouble to clean them, large numbers of beautiful 
forms; and alsoa great quantity of silica. Where did that 
come from? I had seen some certainly in the gizzards of 
birds, where it formed a good substitute for teeth, but of what 
earthly use could be such flinty particles as were contained in 
my residuum of guano, after washing in water for weeks, and 
boiling in hydrochloric and nitric acids? What could they have 
to do with crushing the food of sea birds? Hundreds of 
them, thousands, could have passed at one time through the 
eye of a needle, and millions had to be elutriated before one 
could get the coveted prize—a good slide of the smaller 
diatoms. 
These forms were, of course, all marine; and as a sys- 
tematic study of them, before passing through the intestines 
of the sea bird, was out of the question, one was naturally led 
to investigate the nature of the diatoms of our own waters. 
In these you can find all that is necessary to enable you to 
form an adequate conception of these deeply interesting and 
remarkable organisms; and of the part they take in the 
system which keeps the earth as it is—a beautiful whole. I 
do not say there are no difficulties. There are many great ones; 
and so there are in everything that is worth doing, but I do 
say that, in our local waters, we have great facilities for 
successfully prosecuting our study of the diatom, its habitat, 
nature, development, mode of increase, and preservation. 
First, as to its habitat. Itis found in all rivers, ponds, pools, 
and ditches, and sometimes manifests its presence in a manner 
not altogether agreeable to the nasal organs. This, however, 
is owing not to anything offensive in itself, but to the 
negligence or the want of forethought in man. Diatoms, for 
the most part young ones, together with rising generations of 
plants of a confervoid character, may be nowhere seen to such 
advantage as on the Waddon mill pond. At certain seasons 
the surface of the pond is clear; at others, a thin whitish 
film, showing the direction of the current towards the mill, 
and another film, from the mill to the outlet to the backwater, 
may be seen forming a curve from one side of the pond to the 
other. The gentle current carries it slowly and surely toa 
bridge contrived to stop circulation. Here it is stopped, and 
other portions of the film, which sometimes covers half the 
surface of the pond, are brought in succession to the same 
spot; and, finding no mode of exit at the time, form by pres- 
sure a corrugated mass assuming many colours, and evolving 
