36 REPORTS ON THE STATE OF SCIENCE. 
of 3, and for values of « greater than 10, can be computed to six places 
without sensible error. 
It is to be noted that the Neumann function Y,(x) can be calculated 
from the same data, for 
log LY,,(x)—(log, 2—y) J,(x)} 
ome 2 1 . Tv T. 
=log { Ra/=} —4} log x+log sin (2ta—7—n5), 
y being Euler’s constant. {log, 2—y=0°1159315.. .] 
The Committee are at present engaged on the tabulation of K,,(x), and 
hope to make some additions to the British Association Tables of 
I,(x) which are to be found in the Reports for 1889, 1893, and 1896. 
They are also considering the advisability of collecting all existing tables 
of Bessel functions and publishing them as a single set of tables ina form 
easily accessible to all students. 
The Committee desire reappointment without a grant. 
Magnetic Observations at Falmouth Observatory.—Report of the 
Committee, consisting of Sir W. H. PReEcE (Chairman), Dr. 
R. T. GuazEBRooK (Secretary), Professor W. G. ApAms, Dr. 
CHREE, Captain Creax, Mr. W. L. Fox, Sir ARTHUR RUCKER, 
and Professor SCHUSTER. 
Tue results of the magnetic observations at Falmouth Observatory 
for 1908 have been published in the Annual Report of the National 
Physical Laboratory as well as in that of the Royal Cornwall Poly- 
technic Society. The mean values of the magnetic elements for 1908 
were :— 
Declination . ; " : E 17° 54"7 W. 
Inclination P ‘ : F ‘ 66° 314 N. 
Horizontal Force. : ; 4 0°18798 C.G.S. 
Vertical Force . A ; F : 0°43279 C.G.S. 
The accuracy of the work seems to be satisfactorily maintained. 
Throughout the year Mr. Kitto has been regularly contributing par- 
ticulars of the daily magnetic condition as regards disturbance to the 
international tables which are at present prepared at de Bilt, Holland. 
Dr. Chree has recently been engaged on a comparison of the mag- 
netic disturbances recorded at the winter quarters of the National Ant- 
arctic Expedition of 1902-4 with those recorded simultaneously else- 
where, and has found the Falmouth curves very useful for this purpose. 
It is found that for purposes of intercomparison, disturbances of com- 
paratively small size when of short duration are in many respects 
simpler to deal with than the larger disturbances during which rapid 
oscillatory movements take place. But in handling the smaller dis- 
turbances, and in settling the exact times of their occurrence, it is of 
special importance to have curves whose edges are sharp and which 
are not blurred and indistinct through the disturbing effect of electric 
trams. Thus the undisturbed position of Falmouth proved of very 
material assistance. 
The comparison of magnetic disturbances is a subject to which in- 
creased attention is being given, as evidenced, for instance, by Prof. 
Birkeland’s recent important work on the subject. 
