802 REPORT—1899, 
certainly be overcome, should the members of the British Association at this 
meeting agree to place in the hands of their President a sum of 50,000/., so that the 
total amount available for Antarctic exploration would become something like 
150,000/. Although there is but one central] Government, surely there are within 
the bounds of this great Empire two more men like Mr. Longstaff. The Government 
has suddenly placed the burden of upholding the high traditions of Great Britain 
in marine research and exploration on the shoulders of her scientific men. In 
their name I appeal to all our well-to-do fellow-countrymen in every walk of life 
for assistance, so that these new duties may be discharged in a manner worthy of 
the Empire and of the well-earned reputation of British Science. 
The following Papers and Report were read :— 
1. On Polar Exploration by means of Icebreakers. 
By Admiral Maxarorr, Imperial Russian Navy. 
The steel steamer Zermak, of 8,000 tons displacement, was specially built for 
use as an icebreaker for keeping open the route to Baltic ports in winter and 
through the Kara Sea in summer. The trial trip of the vessel to the Arctic ice 
north of Spitzbergen was described, and its advantages of strength, speed, and 
comfort over all previous exploring vessels were explained. 
2. Physical Observations in the Barents Sea. By W.S. Bruce. 
3. Report of the Committee on African Climatology. See Reports, p. 448, 
4, Setsmology in relation to the Interior of the Earth, 
By Joun Mine, /.K.S, 
After the blow or blows have been struck which cause an earthquake a flood 
of motion sets out in all directions over the surface of the earth, and in all direc- 
tions through its interior. That which passes over the surface does so in waves 
which, whilst travelling at a fairly constant velocity, increase in amplitude and 
period. The waves which pass through the interior travel swifter and swifter the 
nearer their path is to a diameter. Ata distant station the first motion recorded 
is that which has travelled through the earth, and the last that which has travelled 
round its surface. Intermediate motion would be that which had passed through 
the earth and then completed its journey to the observing station through the 
surface. Observation shows that the average velocity with which waves pass 
through the earth varies with the square root of the average depth of the paths 
they follow. Coupling this observation with the knowledge we possess respect- 
ing the density of our world as a whole and the density of the materials on its 
surface, Dr. C. G. Knott shows that the elasticity which governs the transmission 
of the precursors of the real earthquake increases at a rate of about 1 per cent. for 
every mile of descent. 
The second section of the paper treated of the motion following the 
originating blows of an earthquake. It was a common observation to find 
that large earthquakes are a few minutes later followed by other violent disturb- 
ances, and because these second shocks had characteristics similar to the first ones 
they might be regarded as ‘echoes.’ Such symmetrical repetitions, which were 
illustrated by seismograms, indicate that we were not dealing with irregular 
adj ustment of fractured materials, but with phenomena analogous to musical rever- 
erations. 
