133 
BY THE USE OF KITES OFF THE 
WES'r COAST OF SCOTEANH, 1902. 
The distinction between the two cases is not so easily drawn in practice as might be 
supposed. 
The direction of the wind was observed at the surface, and is represented by arrows 
at the base of the diagram. The direction of the wind in the upper air was estimated 
by the direction of the kite wire, and is indicated by arrows at the top of the 
isotherms for the different days. In making the estimate the motion of the vessel was 
allowed for, but the estimates do not claim minute accuracy. On every occasion on 
which a difference of direction is shown in the upper current the wind had veered 
aloft. 
The weather on the days of the ascents is indicated In’- letters of tlie Beaufort 
scale at the foot of the diagram. 
"Temperatiire Gradients. 
From the diagram a table (Table A) of results for temperature variation with 
height for each 500 metres on each day of ascent has been compiled. In each case 
the figures represent the/«// of temperature for the range of height specified. The 
differences of temperature are given to the nearest half degree only. Some of the 
numbers for the last step of height have been obtained by extrapolation for a short 
distance of height when the diagram did not actually reach the up})er limit. Such 
numbers are enclosed in square brackets. 
For the purpose of a comparison, vhicli will be referred to later on, the differences 
of temperature between the sea level at or i^ear Cilnan and the top of Ben Nevis 
have been added. 
In order to complete the comparison of the variations of temperature gradients 
with the meteorological conditions at the time of observation, reference may be made 
to the barometric curves for Fort William and Beir Nevis, which are plott-^d above 
the diagram from the hourly observations fiu’warded to the Meteorological Office, and 
to the charts of tlie paths of depressions in the monthly summaries of the “Weekly 
Weather Ileport” for July and August. The latter are reproduced in fig. 5, The 
position of the sea area at which the series of observations were made is indicated 
by a small circle on the maps. As a matter of fact, the barometric variations were 
comparatively inconspicuous during the period of observations, and the weatlier 
presented a succession of nearly calm days of a somewhat uninteresting character. 
Barometric observations were also made at Crinan, and they Iiave been utilised in 
the comparison, but the variations follow so closely the Aurriations at Fort William for 
which a continuous curve is available that it has not Ijeen thought necessary to 
represent the Crinan observations on the diagram. 
The conditions under which the kite ascents Avere made during the period of the 
experiments tended to confine the higher ascents to days upon Avhich the Aveather 
has a particular feature, namely, a nroderately strong Avind in the upper strata. 
