ON SEISMOLOGICAL INVESTIGATION, 209 
The United States Monthly Weather Review for January gives the 
following note :— 
‘Reports from Mexico describe the earthquake of Monday evening, 
January 24, as the severest ever known in the City of Mexico. The first 
oscillation began at 9:09 (local time). It was from north-east to south- 
west, and lasted Im. 56s. Three minutes later came a second shock, 
which lasted 5s., oscillating north-west and south-east. The earthquake 
was felt over the entire Republic of Mexico. At Colima it lasted 
Im. 20s.; at Vera Cruz it lasted 10s. But few reports of this earth- 
quake have been received from the United States, although it must 
have been feebly felt at many stations. 
‘At San Barnardino, Cal, a shock was felt at 4.55 pm., 
January 25. The newspapers of that city state that the shock was of 
little greater severity than usual, and that the barometer dropped from 
30:12 to 29°86, “an unusual occurrence, &ec.”’ 
Mr. O. H. Howarth, who is interested in recording earthquakes, 
writes to me from Hacienda de Zavalita, Oaxaca, Mexico, as follows :— 
‘T think you may be interested to have a local note about the earth- 
quake shock which occurred here on Tuesday, January 24, being the 
longest and strongest I have yet experienced in this country. The time 
was 5.25 a.M., and the duration, as near as I could get it, 20 seconds. We 
are situated here about 13 miles south-west of the city of Oaxaca, in a 
winding cajion, well up into the mountain range: altitude, 6,200 feet. 
We seem to be all agreed that the wave approached from thesouth. The 
formation of the whole district here is a very hard gneissic granulite in 
which occur the quartz veins with gold. The feature which struck me 
most was the sensation (which I have not experienced before), of the 
wave grinding its way through a hard resisting medium. Just at the 
climax there was a peculiar jerk, as if it had changed its direction, or met 
with some exceptional obstruction. The noise was considerable, and 
some of our people were on their knees saying their “ Ora pro nobis” with 
great vigour. One of them told me to watch the clouds, and for three 
hours afterwards I noticed heavy mist down upon the high ridge at the 
head of the cafion (8,700 feet), which otherwise we never see at this time 
of the year—the middle of the dry season. I cannot see any direct 
reason for an atmospheric change, but there is no doubt that a big 
condensation occurred. The shock seems to have been unusually long 
and severe in the city of Mexico (200 miles north from here)— 
Im. 36s. (this I doubt), and damage was done at some points; but 
probably the accounts which reach England will be exaggerated as 
usual,’ 
On May 29 Mr. Howarth again wrote me, saying that in Oaxaca 
where he was (200 miles south from Mexico City), there was a severe 
shock at 5.25 a.m., a slight tremor about 11 a.m., and another slight 
shock about 5 p.m. In Mexico City this was reversed, the slight shock 
being at 5.23 a.m. and the heavy one causing damage about 5 p.m. The 
first coming from the south to reach Mexico City would have to traverse 
the great range of Popocatepetl, Ixtaccehuall, and Ajusco, by which it 
would be absorbed or diverted, and therefore whilst strong in Oaxaca, it 
would be feeble in Mexico City. If the second came from the north or 
1899. P 
