ON BRITISH COLONIAL MAGNETIC OBSERVATORIES. 355 
With the thermo-electric pile as before, this gave, 
Directed to zodiacal light, summit.2° 
„ zodiacal light, base. 4 ° 
„ sky over sun ............. 0° 
With a tallow candle at 10 metres distance (whether witli the lens is not 
stated, but probably with it, as the experiments would not otherwise be com¬ 
parable),— 
With the condensing cone, deviation. 15 °. 
This, he observes, shows “ combien est miuime la quantite de chaleur 
etivoyee par la luwicre zodiacale, et que 1'inHuence de la comete doit etre 
reellement imperceptible par notre temperature.” 
It was perhaps this somewhat ambiguous sentence which led Humboldt to 
represent these experiments as showing no sensible effect due to the zodiacal 
light (‘Cosmos,’ Note 98, p. 394, vol. i. Sabine’s translation). 
lu the lace of the experiments, however, we must adopt another interpre¬ 
tation; a„d perhaps what the author means is the distinction between the 
ramant heat affectingtlic thermoscope, and the temperature communicated 
to the atmosphere ; which are manifestly different things. 
ike experiment with the caudle, if made (as seems to he implied) with the 
, f , an important verification of the fact of the heating power belonqinq 
® ogld from terrestrial sources. 
iJ^^ult wiih the zodiacal light also shows that at least a portion of its 
My cooling^ SpCcieS ' a,,d ,l0t de P ende,lt 00 to mere loss of heat as a hot 
It is, however, but right to add, that indications of such extreme delicacy 
too liaUn referred t0 ’ ha ? e been ,ooked upon by some physicists as almost 
o liable to uncertainty to be entirely trustworthy. 
On so m of the results obtained at the British Colonial Mannetic 
Colonel Edward Sadine ’ v - pjl8 - 
Nation inf!!? Wl ‘ ic ! 1 , t0 ® k P ,ace at Newcastle in 1838, the British Asso- 
ciation in fulfil „ i i'dh-usui, m io,)o, me untisn asso- 
i'-Hituted _! , T'r • * he first a,nu,, K 8t tJi« objects for which it was originally 
scientific • gmilg a stronger impulse and a more systematic direction 
thS!S , “ reC ° mmCn , ded t0 1,er Government the pro- 
vaiicenipnt n r*i? eX P® ns e ot researches which were required for the ad- 
of iDdividli Ini ' Sclonce t of terrestrial magnetism, but were beyond the means 
t.iL h..t to Carf y 0,,t ’ 1 he8 ° researches were of two kinds, having differ- 
for which" , res P ect,s connected objects. By one class of observations, 
*- - ! ne . aK1 °* naval expeditions to unfrequented parts of the ocean 
Was renuirod it.. , . , cxpwuuona to untrequented parts of the ocean 
®f thejrlobe’nf dc8Kcd . t0 ? de termine the distribution in different parts 
^taction and lirtwi* 1 *®? 611 !* forc ‘ : of t,le eanh In its two manifestations of 
n '®de at stationary ac,l . on - % the other class of observations, to be 
distant from each mbl? °- r ‘? P aC , e< at P oint9 0, ‘ t,,e earths surface very 
toe particularities nf J od,c,oa % selected, it was proposed to ascertain 
Jrar I n all f han ? G « found to take place from y 
force, bv Ibini. It he le 1,1 tkc direction and intensity of the ma 
ear to 
’"rce, by whieii 1,1 tllc direction and intensity of the magnetic. 
® D y otie epoch -! e Iua £ n . cdc 8tatc of the earth corresponding to 
hematic order whirbm^T 1 7fu G ’ Insensil), y> but with a regularity and sy- 
nfest the existence of natural causes as vet unknown 
2 a 2 
