30 THE ANTARCTIC MANUAL. 
in units of the centimetre-gramme-second system. For stations in 
lower latitudes the following scale of sensitiveness is desirable :— 
Declination .. «2... «2... 1 min. of are. 
Horizontal force... «2 .. SY 
Vertical force .. 0... ww we OY 
It is desirable that at temporary observatories the zeros of the 
instruments should be ascertained between the term days by means 
of absolute measurements, and the sensitiveness of the instruments 
should be tested several times a year. 
8. The Absolute Instruments—It is desirable that the permanent 
observatories, either before or during the period of joint observa- 
tions, should carefully test the constants of their standard instru- 
ments, and make a fresh series of comparisons amongst themselves. 
The absolute instruments of the temporary observatories, which serve 
to standardise their variation instruments, must be compared with 
the standards at home before starting, and again after their return. 
9. Observation Forms.—The office of the Seventh International 
Geographical Congress in Berlin will send a specimen of Observation 
Forms, in which the terminal observations are to be entered, to each 
of the co-operating stations. 
