334 Lieut . Drummond on the means of facilitating the 
Slieve Snaght, the highest hill of Innishowen, about 2100 
feet above the sea, and 15 miles N. of Londonderry, forms an 
important point in the triangulation, which connects the 
North of Ireland with the western islands of Scotland. 
On the 23d of August last a conspicuous object was placed 
on its summit, that it might be observed from the Divvis 
Hill, near Belfast, where we were then encamped. Having 
continued, however, till the 26th October, enveloped in a 
haze so impenetrable as to render unavailing every effort 
made for this purpose, Colonel Colby resolved, although the 
season was far advanced and the weather unsettled, that an 
attempt should be made to surmount this formidable obstacle, 
by the aid of the instruments now described. By his direc- 
tions I proceeded with a party of men to the hill in question, 
which we reached on the 27th October. For the first ten or 
twelve days after our arrival we had to struggle against 
most tempestuous weather, and being only provided with 
round tents, which resisted but for a short time the violence 
of the successive gales, it was with some difficulty and exer- 
tion that we maintained ourselves on the hill, and preserved 
the instruments themselves from destruction. At length, 
however, the weather becoming moderate, both instruments 
were brought into use, and we had the satisfaction of learn- 
ing from Lieutenants Henderson and Murphy, to whom 
Colonel Colby had confided the task of completing the obser- 
vations, and whose vigilance the first glimpse of the light did 
not escape, that on the ,9th and 10th of November both 
instruments had been brilliantly visible, and the observations 
in consequence brought to a satisfactory conclusion. The 
distance between the stations is 66 £ miles ; but the difficulty 
