JxiLY 28, 1905.] 



SCIENCE. 



123 



= 36° 13' N. 

 X=140°06' E. 

 H = 870 meters a. s. 1. 



The main building is constructed of massive 

 wood on a solid stone f oiindation and is cov- 

 ered with zinc plates for protection from 

 moisture. The building contains an instru- 

 ment room, a workshop, an office and rooms 

 for the staff. The observatory is perfectly 

 equipped with meteorological and seismological 

 apparatus of the latest designs. A few yards 

 north of the building there stands a high 

 tower of iron construction (11.6 meters in 

 height), on the top of which an anemometer 

 rests. Prince Yamashina's self-registering 

 anemoscope, Robinson's anemometer, Jordan's 

 sunshine recorder and Richards's anemograph 

 for the registration of the vertical component 

 of the wind, are all placed on the upper plat- 

 form of this tower. To the west of the main 

 building stands a thermometer shelter, in 

 which thermometers, psychrometers with Ass- 

 mann's ventilation arrangement, a hair-hygro- 

 graph and a thermograph of largest model are 

 kept. Under this shelter, ten earth-thermom- 

 eters are buried at different depths below the 

 earth's surface, with perfect arrangements for 

 the measurement of the surface and under- 

 ground temperatures. 



On the roof of the main building there may 

 be found a lightning rod, wind vane, self- 

 registering and ordinary rain gauges and an 

 anemometer. The instrument room is ele- 

 gantly equipped with the best meteorological 

 instruments, the more noteworthy of which 

 are Richards's barograph of largest model, 

 self-registering pluviometers, anemometers, 

 mountain barometers, etc. These are placed 

 on stone piers. 



It is worthy of special mention that macro- 

 and raicro-seismographs have been installed 

 on a granite pier which rests on a gigantic 

 rock. One of the seismographs is the famous 

 horizontal pendulum seismograph devised by 

 Professor F. Omori, the illustrious seismolo- 

 gist of Japan. All seismographs, including 

 Gray's conical pendulum instrument and 

 Ewing's horizontal pendulum seismograph, 

 record ordinary or strong earthquake motion. 



but fail to give reliable records of the very 

 small or slow motions accompanying earth- 

 quakes and of pulsatory oscillations. Pro- 

 fessor Omori has adopted the conical pen- 

 dulum and has constructed a seismograph 

 which can be made to give records not only 

 of earthquakes, both ordinary and strong, but 

 of very small or slow movements of the earth, 

 accompanying earthquakes or due to distant 

 earthquakes, of pulsatory oscillations and of 

 slow changes of level. 



In the International Seismological Con- 

 gress, which was held at Strassburg in 1901, 

 Professor Omori pointed out the importance 

 of seismological observations on mountains 

 and high elevations. No country had as yet 

 undertaken seismological observations on 

 mountains as high as Mt. Tsukuba, until 

 Prince Yamashina equipped his observatory 

 perfectly with seismological instrument-s. 

 Since this establishment, many seismic phe- 

 nomena have been observed, the most extraor- 

 dinary of which were the horizontal move- 

 ments of the earth's crust in January, 1902. 

 The horizontal motion of microseismic nature 

 which was east-westwise began at 11:09 p.m. 

 on the fourth of January and lasted until the 

 sixth. Again a movement of the same nature 

 began on the twelfth of that month and lasted 

 for a few days. The seismogram given by 

 Omori's instrument shows that these move- 

 ments began almost at the same hour on each 

 day and ceased in the same way, and that the 

 curves of oscillations are of the same nature. 

 Horizontal movements of such intense char- 

 acter had never been observed before; the 

 most remarkable fact is that nothing was 

 recorded on the lower level. 



In connection with this observatory, two 

 base stations were established by Prince 

 Yamashina. The first one is situated at the 

 foot of the mountain, at the height of 36 

 meters above sea level. The second was built 

 on the east side of the mountain at the height 

 of 240 meters. All the important meteorolog- 

 ical elements are here observed three times 

 daily, besides being self-registered. 



The personnel of the observatory consists 

 of several observers and computers. As the 

 positions of the director and meteorologists are 



