192 REPORT—1899, 
21. Hawaii: Honolulu. 
On February 19, 1898, the trustees of the Elizabeth Thompson Science 
Fund assigned me a grant of $250 in aid of a seismic survey of the world. 
This was expended in purchasing a horizontal pendulum, which was 
shipped to the care of H.M.’s Consul-General, W. J. Kenny, in Hawaii. 
When Mr. Kenny left Honolulu in March 1899, the instrument was 
handed to Professor Maxwell, who will work in conjunction with Pro- 
fessor Alexander and Professor Hosmer (Principal of the Government 
High School), and the latter, I understand, will kindly make arrangements 
for its installation. Professor George Davidson, Chairman of a Committee 
appointed by the Council of the University of California to undertake 
Seismic Investigations, writes me that Mr. Bishop of Honolulu has promised 
a site for the instrument, and that Professor Alexander will see that it is 
placed in working order. It is hoped that by next year a series of records 
will have been obtained from this exceedingly important station. Copies 
of the report based upon these records should be sent to the Secretary of 
the Board of Trustees of the Elizabeth Thompson Science Fund, Harvard 
Medical School, Boston, Mass., through the liberality of which body the 
Hawaiian Station has been established. 
22. Lgypt: Cairo. 
Captain H. G. Lyons, R.E., Director-General of the Survey Depart- 
ment, writes on June 2, 1899, that owing to structural alterations and 
other causes, it has not been possible to commence continuous observations 
with the seismograph. The instrument was handed to him in February 
last, and in about three months’ time observations will commence. 
23. U.S.A.: Philadelphia, Swarthmore College. Professor 8S. J. CUNNINGHAM. 
When observations commenced at this station Professor Cunningham 
experienced great trouble with ‘air tremors,’ but from the excellent 
character of the seismogram for the Mexican earthquake of January 24, 
1899, it is anticipated that these difficulties have been overcome, but no 
report has been received. 
III. Discussion of the preceding Registers. 
Although in the following discussions a few disturbances are referred 
to in detail, all that is given for the majority are the time entries. 
The first of these refers to the instant when motion commenced at various 
stations. It is the commencement of the preliminary tremors referred to 
as P.T.’s. In the Milne H.P. records these are usually shown as a mere 
thickening of the line. If there is no entry in this first column it means 
that heavy motion commenced suddenly, or else in consequence of move- 
ments due to air currents the commencement of the P.T.’s was not deter- 
minable. The duration of these first P.T.’s, which are regarded as com- 
pressional waves which have travelled through the earth, is given where it 
is possible in the second column. These quantities are not the same as 
those given in the Shide Register, which refer to the duration of all 
movement from the commencement up to the maximum. The time of 
the maximum, which is not the time when the largest group of waves 
appears, but a point usually midway between this commencement and end, 
is noted in the third column. The difference between the first and third 
columns gives the duration of all P.T.’s, and corresponds to entries in the 
Shide Register. The sum of the first and second columns gives the com- 
