922 REPORT—1885. 
point above, holds up the lever by pulling on a point near the fulerum. To make 
the mass nearly astatic the point at which the spring’s pull is applied is situated 
below the horizontal line of the lever, so that when the spring, by (say) being 
lengthened, pulls with more force, the point of application moves nearer the fulcrum, 
and the moment of the pull remains very nearly equal to the moment of the weight. 
Apart from the registration of palpable earthquakes, the inertia method is to 
be applied to the minute earth tremors which have been observed in Italy by 
Bertelli and Rossi, and which are probably to be found wherever and whenever 
one searches for them with sufficient care. But in dealing with them no mechanical 
means of recording can well be applied on account of its friction, and a still more 
frictionless method of suspending the heavy mass is desirable. The writer prefers 
for this purpose a mode of astatic suspension (of which a model was exhibited) 
based on Tchebicheff’s straight line motion; and to detect the movement of the 
ground he observes, by a microscope fixed rigidly to the frame of the machine, the 
displacement of the frame with respect to the suspended mass. This is Bertelli’s 
method, except for the substitution of a nearly astatic mass for the stable mass 
used by him—namely, the bob of a short pendulum—which, of course, gives a 
misleading magnification of certain vibrations. 
The writer was recently requested by the directors of the Ben Nevis Observatory 
to design seismometers for use there, and obtained a Government grant for their 
construction. The equipment at Ben Nevis will include recording seismographs 
and a micro-seismometer of the kind just described. To measure slow earth-tiltings 
an instrument is being constructed in which a modification (due to Wolf) of 
d’Abbadie’s arrangement (described in Professor Darwin’s Reports) is followed. 
Light from a lamp travels some twenty feet horizontally to a mirror inclined at 
45 degrees to the horizon. It passes vertically down through a lens which brings 
the rays into parallelism. They strike two reflecting surfaces—one the surface of 
a basin of mercury, the other a plane mirror very rigidly fixed to the rock. The 
rays come back to form two images near the source, and any relative displacement 
of the two images is measured by a micrometer microscope. In the choice and 
design of this instrument the writer has to acknowledge much assistance from 
Professor G, H. Darwin, This apparatus, like the others, was intended for Ben 
Nevis, but a visit to the observatory there has convinced the writer that to use it 
on that site, and in the atmosphere which prevails on the top, would be a matter 
of extreme difficulty, and that, in the first instance at least, observations should be 
made with it on lower ground. 
14. On the supposed Change of Climate in the British Isles within recent 
years. By Tuomas Heavy, B.A. 
This note gives the result of an examination of the Meteorological Tables 
published by the Registrar-General of Births, Marriages, &c., in Scotland, and 
shows that there has been no material alteration in the mean temperature, either 
of all Scotland or of six stations whose records have been separately examined ; 
but that there has been a decided increase in the amount of rainfall within recent 
years, which increase seems to exhibit itself more particularly on the eastern coast. 
15. On Malvern, Queen of Inland Health Resorts, and on improved 
Hygrometric Observations. By Professor C. Prazzt Smyru, F.R.S.L. 
The conditions for health resorts so often include useful requirements for scien- 
tific observing stations, that the author hoped the identification, chiefly by hygro- 
metrical observations, of a remarkably favourable example of the former, might be 
interesting to a British Association meeting. ; 
Having first carried on several weeks’ observing in a low level region of the 
Midland Counties, he then removed to Malvern Hills with the same instruments, 
and immediately obtained more than twice the amount of depression of the wet 
below the dry bulb thermometer, as ordinarily observed at the tirst station. 
