1921.] The Eighth Indian Science Congress. CXXi 
The influence of forced vibration on the ee magnetism 
. the nickel coherer.—By S. 8S. Mukherje 
y placing two magnetising rie parallel and perpndicalae bad the 
earth’s magnetic field, and by a justing two fixed and o ee 
eee in them, the effect of oie mangnetising field (H) is atin imina 
mea 
coherer is mica sesame vibrated by means of an rec ae 
ca. ‘fork and its true magneti s studied under two condition 
(1) pane o superpos aa on constant field. 
(2) Change of field superposed on uniform vibration constantly 
act, a 
li i aa phcnagsss A impressed increase 4nI-NI (by about 2%) 
up to a steady m um. s change is — pe wep it per 
for a very long se: and can is carrie and superposed on oe 
inductions at different Bag Reversals cate ‘with lowering of the field 
= A 3°? 
emperature pe remaining cons the increase in 
(4nI-NI) due to vibration 4 is a) directly ie eee <e ‘C the field (H) in 
which the pide is vibrated . (ii) inversely propo ortional és: the least 
time (T) of vibration necessary to bring about this increase 
Vivstion heaped the eehontton:; the coercivity and the area of a 
4nI-NI 
—— cycle. 
. Bie aie constantly acting. vast rkably lessens time-lag and 
hyste The true magnetism (4n7I-NI) more ze roeny and more quick- 
ly hows. any change in the eaguntneng To for 
4nI-NI : 
The symmetry of ag eurves.—By S. S. Mukherjee. 
; ; : . 4nI-NI) 
This paper describes an interesting relation observed in as 
curves in the case of the ferromagnetic substance tudied, namely t 
ad area is proportional to the product of the scant and the Aare 
Recent advances in seasonal weather forecasting. —By 
G. T. Walker. 
author describes the recent sng of his extended examination 
necting Indian uch 
to a e correlation connec ainfall egy with s 
physical elements pp t pee cise a control. By means 
f curves of actual rainfall distribution and th ee ae recognised in 
1908, an n 1920, at improvemen hich have 
ws t 
the ial aid aff forded by the Upper r Air Observatory at Agra 
in » preparing s Tocuiats of the cold weather rains of nor rthern India. 
Notes = noe newly designed physical apparatus.—By- 
iS. ON. ra. 
been car- 
The paper contains an account of further work that has 
i i , Sibpur, in the way of 
ried out at the Bengal Engineering a a p po har Rare 
rt descripti f appa- 
paper containi short des rs gant ‘of twelve asda ° : 
ratus, spec sae designed for lec demonstration an roy engin 
tary practical classes in physics ie submitted by the author. ‘ i. 
paper he suggests that the manufacture of scientific instruments mig 
