34 Scientific Proceedings, Loyal Dublin Society. 
T am indebted to Mr. R. G. Norman for many specimens of 
Trish and other Kieseleuhrs which I have examined. Under the 
microscope the Kieselguhr from county Antrim presents a very 
pretty appearance, showing innumerable little cubical box-shaped 
diatoms, alsolittletubs or drums in less quantity, anda few elongated 
and boat-shaped diatoms, apparently of the kind known as pinnu- 
larize and Navicula Westii ; there are others of a star or radial shape, 
but the neatly shaped cubical boxes are the predominating form. 
A curious fact was noted that in focussing for the boxes the large 
boat-shaped and radial diatoms almost disappeared, and that when 
they were brought out clearly the boxes became very indistinct. 
On measurement the width of the little box-shaped diatoms is 
found to be about 34, mm. 
This illustration shows the highly magnified image of the box 
and tub-shaped diatoms. 
The raw Kieselguhr, as cut from the deposit and sun-dried, 
has a specific gravity of ‘5422; when moulded in a brick, and 
burned at a very low temperature, it was found to have a density of 
8073. When burned at a somewhat higher temperature it takes 
a light red colour, and has a density of :7691. 
A piece of burned Kieselguhr of 54:87 grams absorbed on 
immersion 88 grams of water, having then a weight of 92°87 
