108 REPORTS ON THE STATE OF SCIENCE.—1912. 
tion of the Rev. W. O'Leary, $.J., so far as the funds at the disposal 
of the Committee would permit. 
As the cost of hiring cylinders for hydrogen for the ascents was 
considerable, it was subsequently decided to purchase a cylinder, and 
accordingly an 80-foot cylinder and cover were obtained from the 
British Oxygen Co., Glasgow. This, at a cost of 31. 3s. 9d., holds 
sufficient hydrogen for the single and short series ascents, but an 
additional cylinder is necessary for the long series of ascents extend- 
ing over a week. 
Ascents have been made in September, November, December 1911, 
and January, April, June 1912. No ascents were made in March and 
May owing to unfavourable weather conditions. The ascent could 
not be made in February through the delay in getting hydrogen owing 
to the dock strike at Glasgow. 
Particulars of the ascents, including the date and time, the height 
reached, and the conditions of the pressure distribution at the time are 
given in Table I. The detailed values of the temperature at different 
heights are given in Table IT. 
Out of the fourteen balloons liberated seven have been recovered, 
giving six good records to heights of 13 to 18 kilometres. In all six 
cases the stratosphere was reached. Out of eighteen balloons liberated 
since ascents were begun at Mungret College in June 1911, ten have 
been recovered, giving nine records to heights varying from 13 to 
21 kilometres. The .average height of the stratosphere from these 
ascents is 10°7 kilometres, which is very nearly the same as the mean 
height for England. The majority of the ascents relate, however, to 
the summer and autumn months, when the mean height is greater 
than usual. The pressure was also above the average at the time of 
the ascents, the mean for the nine occasions being approximately 
764 mm. for M.S.L. Thus, so far as these ascents give information as 
to the average state of affairs, the results indicate that the strato- 
sphere is lower over Ireland in the summer and autumn months than 
it is over England or the Continent. 
It ought, however, to be pointed out that the ascents were made 
for the most part during a period when there was a gradient for 
northerly winds, and it is under such conditions that low values of 
He appear to occur in other places. 
Three ascents made in Ireland, in July 1908 and August 1910, by 
Captain Ley, gave a higher value for the mean height, 11.7 kilometres, 
corresponding with a mean sea-level pressure of 767 mm. If account 
is taken of the pressure and of the season the value is, however, not 
greater than the mean value for England or the Continent. (The value 
of He increases by about 0.5 kilometre for each 4 mm. increase of 
pressure. ) 
None of the seven balloons sent up in December 1911, January 
and April 1912, were recovered, but as only one balloon was recovered 
out of eight sent up by Mr. Dines at Pyrton Hill in the same period, 
it is probable that the losses are to be attributed to the special 
character of the weather rather than to the situation of the station. 
The results obtained are indeed very gratifying, and the best thanks 
