between the Observatories of Armagh and Dublin. 127 



establish my party at the mountain. This month was found by the officers of 

 the Survey favourable for their w^ork, and I knew it to be equally so for 

 astronomical observations. On arriving, I found all difficulty removed by the 

 kindness of Dr. Campbell, the rector of Forkhill, who had, with the hospitality 

 for which he is remarkable, even in Ireland, provided such assistance that we 

 were able to have the tents pitched, and the stores arranged within a couple of 

 hours ; nor was his attention bounded with this, but continued during the 

 whole of our operations.* 



The wind blew furiously from the N.W., and next day the snow fell several 

 inches deep on the mountain. I had not reckoned on such weather, but the sky 

 was clear at intervals ; and I knew that even a gale will not affect the ascent of 

 a well proportioned rocket. I therefore left my eldest son, Mr. T. A. Robin- 

 son, in command of the party, with directions to commence firing at ten, 

 and give a signal every five minutes, as far as twenty, unless the night was 

 decidedly cloudy. It would have been better to have arranged signals with 

 him, but in my uncertainty of the quality of the rockets, I was desirous to 

 economize them as much as possible. 



Sir W. Hamilton (H) and myself (R) had arranged a list of stars to be 

 observed daily, and, as I have stated. Lieutenant Larcom had given us the means 

 of directing our instruments to the mountain with astronomical precision. The 

 signals were, in fact, visible at Dublin, when the weather was fine, by the naked 

 eye, but this could not be trusted to in moonlight or cloud, and they were observed 

 there with Sharp's equatorial, whose telescope, by Cauchoix, has an object glass of 

 flint-glass and quartz, 5'". 2 aperture, with a power of 54. The time was 

 noted by Arnold's clock. At Armagh the locality permitted the use of more 

 instruments. My assistant, Mr. Edmondson (E), observed, by the transit clock, 

 with a 3<} feet achromatic, by TuUey, of 3'". 2 aperture, power 30, placed at the 



* The tents were pitched at the cairn, which is the trigonometrical point of the Survey. It is 

 of great size, and contains a sepulchral chamber, in the form of a cross. The peasantry open it with 

 great reluctance, and close it as soon as possible, believing it the dwelling of a sorceress, one of 

 whose feats is given in Miss Brooke's Relics of Irish Poetry. Afterwards, when the weather 

 became still more tempestuous, they were moved about 600 yards northward, near the lake which 

 is found on this lofty summit. This new position is about 100 feet lower, but the rockets were 

 much too powerful to make this of any consequence ; they might in fact have been fired in the 

 valley of Forkhill, had I been aware of their excellence. 



