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due to electrical action, or any other non-mechanical cause? 
If I be not greatly deceived, they all form a most complete 
whole, if viewed in the light I have placed them in ; whereas, 
so far as I can see, they are quite incomprehensible on the 
latter supposition ; nor, so far as I can learn, have its most 
zealous supporters ever given any satisfactory reason for the 
manner of distribution of the cleavage planes, even assuming 
them to be as regular and uniform as some authors appear 
to describe them. Mr. Sharpe's theory, of course, only 
differs from mine in his assuming that the particles have 
been really compressed ; whereas I am persuaded that in 
general they have only suffered a change of position. This, 
however, no doubt resulted from the different method of 
research I have adopted. It would, however, cause me to 
extend this communication to too great a length to enter 
fully into all these questions, or describe many other facts I 
have observed connected with the subject. My object, in 
the present paper, is to give a rough outline of my obser- 
vations and theories ; and though it is already rather long, 
yet I fear many points will have been far from understood, 
for to explain them all would require much detail. 
A DESCRIPTION OF THE HYDROSTATIC MACHINERY AT GREAT 
GRIMSBY DOCKS. BY GEORGE BROADRICK, ESQ., C.E., 
OF HAMPHALL STUBBS, DONCASTER. 
The class of machines under notice in the present paper 
presents few varieties of principle or construction, and pre- 
vious to the invention of Mr. Armstrong's machinery, the 
only examples of it were to be found in the hydrostatic 
press of Mr. Bramah, and the water-pressure engine, the 
latter of which had come into use to a very limited extent. 
The machinery, of which such excellent examples are now 
to be found at Grimsby and many other places, was first 
