6 
THE GEOLOGIST. 
elude in my abstract. "When tlie boilers of steam-ships are being 
cleaned, procure portions of the calcareous deposits scaled off the 
interior, and by treating them in the usual way with nitro-muriatic 
acid, Diatomacean-ioYins and Pohjcystina-sheWs may be detected in 
considerable quantity. 
By obtaining these deposits from ships plying within known limits, 
a series of free floating Diatom acece might be secured which would 
afford good data for the ascertainment of their range, distribution, 
and limits. And so, heartily thanking Dr. Wallich for this crumb 
of friendly feeling, I close his pamphlet. The year that has just 
departed has thrown no light of equal importance on geological history ; 
though it has been a very notable year in geological science — 
notable in the importance of its discoveries, thoughtfully made, and 
carefully introduced ; and beyond measure notable in its crop of 
theories, and in the agitations produced by them. But of these latter 
"helps to knowledge" we have surely had enough. Dr. Wallich has 
sent the ball rolling in another direction ; and his labours are more 
clearly reflected in the mirror of Truth than is any attempt to claim 
creative power for the working of secondary principles. 
A CHBISTMAS LECTURE OIs" "COAL" 
By J. W. Saltek, E.G.S. 
Not a great many years ago the " bigwigs" in England were 
assembled in conclave, and the elite of science was called before them. 
There were a great many lumps of a blackish-brown substance on the 
table, and a great deal of smelling, and burning, and poking of the 
same black lumps by the same " bigwigs" and learned men. It was 
the great " Torbane Hill Coal" case. 
" The point was in question, as all the world knows, 
To what the said substances ought to belong." 
Was it pure carbon ? Was it carbonaceous shale ? Was it shale 
without much carbon ? Was it carbon without much sliale ? Was 
it bituminous shale ? Was it coal-shale ? Was it cannel ? Was it coal? 
We are afraid to say how many guineas were spent, or how many 
microscopes were busy in London and Edinburgh. But after all 
