100 



under water or otherwise, from a resort to galvanic apparatus as the 

 means of igniting the gunpowder employed. His efforts had been 

 incited originally by those of a person named Shaw, who had pro- 

 cured a patent for employing mechanical electricity for the purpose ; but 

 who, finding that method of operating too precarious to be useful, had 

 applied to Dr. Hare to acquire a knowledge of more effectual means. 

 This led to the experiments of which the result has been published, 

 both in the newspapers, and in the Journal of the Franklin Institute. 

 The subject was now referred to, in consequence of the recent publi- 

 cation of analogous experiments by his friend, Professor Daniell, of 

 King's College, London, who, in the case in point, no doubt as in that 

 in which he had " reinvented''' Dr. Hare's concentric blow pipe, was 

 ignorant of the results previously obtained in this country. 

 Professor Daniell had, in blasting, used the highly ingenious appa- 

 ratus known as "Darnell's sustaining battery" the contrivance of 

 which had done him great honour; but Dr. Hare conceived that how- 

 ever preferable might be a battery of that kind, in processes requiring 

 a permanent current; for a transient energetic ignition, such, as is most 

 suitable for blasting, the calorimotors which he had contrived, would 

 be decidedly more efficacious. 



Dr. Hare further communicated the results of his recent ex- 

 periments to obtain calcium, as follows : — 



By igniting an equivalent weight of lime with an equivalent and a 

 half of cry stallized bicyanide of mercury , in two successive experiments, 

 residual masses were obtained, which, within a small fraction, had the 

 weight which would have resulted from the union of an equivalent of 

 calcium, with an equivalent of cyanogen. A portion of the compound 

 thus made, was placed between electrodes of charcoal, the lower piece 

 being excavated slightly to receive it, and the upper one being so shaped 

 as to enter the cavity. The electrodes were severally supported by cop- 

 per rods passing through stuffing boxes, so as to be included within a 

 glass receiver, ground to fit air tight upon an extra air-pump plate. 

 In consequence of this arrangement, the receiver could be exhausted 

 of air, and the electrodes consequently situated in vacuo, or in an at- 

 mosphere of hydrogen, as might be deemed preferable. The lower 

 electrode formed the cathode, the upper the anode, of two hundred 

 pairs, each comprising one hundred square inches of zinc surface. 

 Under these circumstances, when the circuit was completed, by 

 throwing the usual charge of acid upon the plates, the most intense 



