302 
The Rev. F. J. H. Wollaston on the 
being at 2 9,9, I begin from the corresponding point on 
Table II, and take out 
1250 parts between 50 and 1300 — 1300 — ij8 22 2982 
»>5 - - * = 3-5 
1251,5 parts, giving the approximate height - 2985,5 feet, 
to this add the correction from Table 111,0,0837x2985,5 22 250,0 
the corrected height from Gregory’s to the summit 3235,5 feet. 
from Vicarage to Gregory’s - - 2 99>5 
from Quay to Vicarage - - . 11,25 
Total from north end of Quay to summit - 3546,25 feet. 
General Roy's measurement trigonometrically makes it 
3555,4 feet, and barometrically 3548,9 feet. 
During the same visit to Carnarvon, I took the opportunity 
of trying the instrument on Moel Elio, which stands between 
that place and Snowdon, and has also been measured by 
General Roy. On September 6 , at the Vicarage, the ther- 
mometrical barometer stood at 737, thermometer 59 0 , baro- 
meter 29,8. In the blacksmith's shop at Waen Fawr, at the 
foot of Moel Elio, water boiled at 550, thermometer 57 0 . The 
instrument was here set to 767, and carried to the summit, 
where by the pile of stones it stood at 25, thermometer 52 0 . 
From Vicarage to Waen Fawr, the difference 737 — 550 — 187, mean therm. 58°. 
187 parts - - -22 441 feet. 
Add correction 0,0669 x 441 =2 29,5 
Corrected height from Vicarage to Waen Fawr - 470,5 feet. 
From Waen Fawr to the top, the difference 767 — 25 22 742, mean therm. 55 0 . 
742 parts taken from 258 to 1000 - - - 22 1766 
Add correction 0,0583 x 17 66 - - 22 102,8 
Corrected height from Waen Fawr to the top ... 1868,8 feet. 
From Vicarage to Waen Fawr - - - - - 470,5 
From Quay to Vicarage - - - - - 11,25 
Total from north end of Quay to top of Moel Elio 
2350,55 f eet * 
