It is singular that this Toadstone has never been introduced 
into Manchester for paving and road making, but that all such 
materials are fetched from Penmaen-mawr, in North Wales, 
when they could be had within a qnarter of the distance from 
Derbyshire by rail and canal. As a quarry is now opened in 
Doveholes, and the stone to all appearance is as hard as the 
Welsh stone, it is desirable that the authorities of Manchester 
and Salford should give the Toadstone a trial, and test its 
capabilities of standing the wear and tear of our main streets 
as a paving stone or road metal. Both the Welsh and Derby- 
shire stones are of igneous origin, and have a nearly similar 
composition. 
Dr. Roscoe stated that he intended to analyze the Derby- 
shire traps, and hoped shortly to lay the result before the 
A Paper was read by Dr. Joule “ On the Utilization of 
the Sewage of London and other Large Towns.” The 
Author having given an outline of the history of the question 
of Metropolitan drainage, expressed his regret that a system 
had been adopted in which the utilization of the sewage was 
ignored, and only the second object, that of increasing the 
salubrity of the Metropolis, was considered. He described the 
works which are now being attempted, and came to the 
following conclusions: — 1st. That under the new system 
greater accumulations of deposit would take place, which, 
being carried into the river by storm overflow, would continue 
to pollute the Thames. 2nd. That the new sewers, being 
composed of brick, would not entirely prevent the ]>ercolation 
of sewage into the adjacent ground. 3rd. J'hat the portion 
of sewage discharged at the outfalls would not be entirely 
prevented from returning to the Metropolis. 4th. That the 
river would be rendered particularly noxious at the point where 
so vast a quantity of offensive matter was to be concentrated ; 
and, in consequence, the large floating ])opulation, as well as 
