hitercourse between London and Dublin. 125 



Cantire. But, instead of finding the distance from 20 to 

 30 miles, as laid down in some of our modern maps, I found 

 it only eleven miles and a half. 



Having ascertained this fact, it occurred to nie, that, 

 although no telegraphic communication can take place be- 

 tween Dublin and Holyhead, in Wales, v.'hich is G3 miles; 

 nor between Drogheda in Ireland, and Port Patrick iu 

 Scotland, which is 25 miles; yet that infornjation mig:ht be 

 easily communicated from Fair Head land, to the Mdll of 

 Cantire, by a telegraph. One thing is certain, that it is 

 nearly as far between the poinlsof communicaiion, by tele- 

 graph, at Puiney, and the one next to it, on the line from 

 London lo Portsmouth, as between Torr Point, Fair Head, 

 Ireland, and the nearest point of land in Scotland ; and that 

 at one place, on the same line of conimunication, the 

 nearest communicatmg pomts, by the telegraph, are nearly 

 thirteen miles distant. 



In erecting a telegraph southward from Dublin to Cork, 

 and northward to Fair Head, there seems no difficulty at 

 all. At Fair Heatl, and the opposite point in Scotland, 

 signals to draw attention might be addressed both to the eye 

 and the ear; those to the ear being calculated to rouse at- 

 tention, and induce people to look out and apply to their 

 glasses. From Cantire, through the Isles of Arran, Bute, 

 and other places, information might be sent by Glasgow, 

 Edinburgh, &c. &c., direct to London, and back again to 

 Dublin, Cork, &cc. &c., in the course of a few minutes. 



Speedy information to and from our fleets in the harbour 

 of Cork, &c., in Jreland, as well as to and from these at 

 Portsmouth, Plymouth, &c. &c., in England, is certainly 

 an object of great importance; and, in my humbic opinion, 

 the only way to have little or no use for soldiers, sailors, 

 ships of war, batteries, cannons, telegraphs, ike, is lo have 

 plenty of them in readiness. 



I remain, sir, yours truly, 



9t. Martin's l.ane, J'AMKS IIaLL. 



August 15, ISOD. 



XVII. A concise Abstract of Professor Mitchill's Dw" 

 courses on Mineralorryy the sixth great Sedion of tha 

 Cou'se of Natural History which he delivers in the new 

 Institution at New York. 



A. i.Mosf immediately on his return home, aflcr ihc tor-, 

 minalioii of the congres'^ona! session on the tiiird-of Ajucli 



1 8(<9i 



