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Proceedings of the Royal Society 
arranged on a horizontal axis, so that by turning a handle they 
might he rotated. There was an apparatus for cleansing the plates 
as they turned, and additional galvanic energy was obtained after 
exposure to the air. 
That was the battery used in blasting the Skerryvore rocks. 
Other papers of his are to he found in the “Proceedings of the London 
Electrical Society,” 1837-40 and 1843, pp. 77, 78, 356-60, “On 
Eadiation not a property of Electricity,” &c., &c. To conclude the 
subject of blasting, it may he as well to say that on the 26 th March 
and 26th April 1838 (at the request of the Highland and Agricul- 
tural Society of Scotland) he exhibited, not only his process of 
blasting rocks, hut that of explosion under water, at Craigleith 
Quarry, for the perfect success of which he received a medal from 
the Society. A drawing of the scene, showing the height to which 
the water rose, was made at the time, and afterwards engraved. 
Some sappers and miners, then present, being taught the process, 
made it known to Colonel Pasley, and the result was his blowing 
up the “Koyal George.” It was not, however, until 1840 that (by 
desire of many) he published a pamphlet, giving simple, practical 
directions for general work, and detailing the use he had made of 
sand for tamping, and the introduction of atmospheric air between 
the charge of powder and the sand, so as to increase the energy of 
explosion. He first pointed out that sand so placed in a tube could 
not he blown out. In the “Proceedings of the Highland and Agricul- 
tural Society” may he seen the original paper, of which the pamphlet 
was a copy, and it was still further illustrated in the “ Proceedings 
of the West Yorkshire Geological Society” for 1842-48, pp. 126-138. 
The last act of the kind he personally superintended was in a quarry 
near Eydal, to please the poet Wordsworth and Dr Davy. In the 
“Mining Journal” a controversy was begun 18th January 1841, and 
ended hv two letters — one from Mr Byers, stating that he had made 
much practical use of assaying ores by galvanism, the idea of which 
originated with and was communicated to him by Mr Eoberts; 
the other was from Mr Eoberts himself, showing that M. Becquerel’s 
essay “ On Detecting Metals in their Solutions ” did not hear on the 
subject, as he did not profess to give any practical method for de- 
tecting the quantity and variety of metals contained in the ore. 
Mr Eoberts set out on a scientific expedition to Norway in the 
