482 MR JOHN ALLAN BROUN ON THE BIFILAR MAGNETOMETER, 
By water experiments, 
q=0-000230 
Therefore, 
[q]=0-689 g. 
31. The quantities in Table IX. have been combined into periods of twelve 
months, and the following results obtained :— . 
1843, August—1844, July. g’=0°72 sc. div. at fea error =0-02 sc. div. 
44.4 Ub o-«\ /2B45, (5 =080 ... = 0-04 
iis, 1846, 066m ass, ctort, SerbtorienlwOs 
1847, ... 1848,Sept. =0-59 ... i, ae O06 
32. The sums having been arranged according to the months, the following 
are the results, each being a mean of jive, excepting those for August and Sep- 
tember, which are the mean of six months :— 
TABLE X.—Sums or DIFFERENCES OF BIFILAR MEANS FOR BACH MONTH. 

















Mean Tem- 
perature of 
Boneh, Bifilar. 
Probable 
Error. 
| pa a ESS 


January, . . . - . . 63°90 
February, . ; : < . : 62:92 
March, ‘ ; : : , : 61°63 
April, : ; , : A ‘ 57°60 
May, : ‘ : 5 . : 53°19 
June, : : ; i j ; 49:36 
July, ‘ F : F ; : 47°73 
August, . . : , , ‘ 49°31 
September, . : ; ‘ : ‘ 52°44 
October, . : ‘ : . ; 55°77 
November, . ad ; : z ; 59-04 
December, . 62°96 

These values have been discussed by least squares, to determine if g’ varies 
with ¢ the temperature ; and the coefficient for +1° Fahr. was found = —0:004 
sc. div., or nearly zero; but the partial values of g’ are too irregular to give the 
conclusion any great weight. The irregularities in the value of g’ can be traced 
in general to large disturbances. 
33. TREVANDRUM, 1842-45.*—The observations discussed include the years 
1842-45 only. The results are as follows :— 
1842, Magnet No. 3, k = 0-:000135. 
* Observations in manuscript. 

