TRANSACTIONS OF THE SECTIONS. 15 
found in the solar-diurnal variation to be as nearly as may be in the inverse ratio of 
the values of the horizontal force at the two stations (which is the antagonistic force 
opposing all magnetic variations), whilst on the other hand the increase in the range 
of the disturbance variation is many times greater than it would be according to the 
same proportion. It would appear, therefore, that the energy of the disturbing 
force must be much greater at Point Barrow than at Toronto. ; 
The author then proceeded to point out the concomitant occurrences of the auroral 
manifestations. The observers noted at each hour whether or not there was an 
aurora visible: from 11 a.m. to 3 P.M. no auroral displays were ever observed ; 
but the number of them was found progressively to increase from 3 P.M. to 1 A.M., 
and then again in regular progression to decrease to 0, at1la.m. The frequency 
of the occurrence of the aurora may be judged of, when it is shown that during six 
months,—December, January, and February of 1852-58, and the same of 1853-54, 
—the aurora was seen six days out of every seven. The hour of the day at which 
no auroral display is ever observed corresponds with the minimum of westerly dis- 
turbance, while the maximum of both is found at the same hour of westerly dis- 
turbance, viz. 1.a.m. ‘The frequency of the aurora, also, and the amount of west- 
erly deflection of the magnet also accord ; whilst on the other hand, the auroral 
hours appear to have little or nothing in common with the turning hours or the pro- 
gression of the easterly deflections. 
When Sir John Franklin was going out on the expedition which deprived his 
country of the invaluable services of himself and his brave companions, he had been 
furnished by the Admiralty with instruments carefully adjusted and compared with 
standards, and with full instructions for their use, and for the making and recording 
hourly magnetic observations in the several stations he might occupy in these seas ; 
and in the last letter which had ever been received from him, he had expressed his 
determination to put up those instruments at the several stations at which he should 
winter. Now when his ardour in these pursuits and that of Captain Crozier, the 
second in command, and the other officers, were taken into account, there could 
remain no doubt that such observations had been made and recorded, and that these 
records may still exist if the ships themselves have not been destroyed. Parties 
quitting the ships with the prospect before them of a long and perilous journey to 
the Hudson’s Bay settlements would not be likely to charge themselves with such 
records, but would leave them, well secured, to be found by those who they might 
naturally expect would be sent to search forthem. He had therefore no doubt that 
if the ships of Sir John Franklin were still in existence, the records of more than one 
winter’s observations would be found in their cabins ; and this was one of the reasons 
why men of science were so anxious to have the ships carefully looked for; it was 
a duty to the memories of those who had sacrificed their lives in procuring these 
and other valuable results, to have them recovered if possible. 
Brief Account of the Construction and Effects of a very Powerful Induction 
Apparatus, devised by Mr. E. S. Ritchie, of Boston, United States. By 
Professor W. B. Rogers. 
In this the secondary coil is formed by winding the wire in such manner as to 
make a series of fiat spirals, having each the thickness of a single wire, and thus 
building up the coil by thin transverse strata. The primary coil is covered by a 
gutta-percha tube, and this by a closely fitting bell-glass, knobbed at the upper end, 
and having a widely expanded lip below. Over the whole is placed the secondary 
coil. By this arrangement the discharge between the core and the secondary coil 
is effectually prevented. Very perfect means are used for preventing any discharge 
within the secondary coil, between its different parts. With a secondary coil of 
30,000 feet of wire, No. 34, and using one Bunsen cell, this apparatus gives a spark 
6 inches in length. When the coil is increased to 50,000 or 60,000 feet, and four 
cells are used, the spark is lengthened to upwards of 10 inches, and has been passed 
continuously through an interval of 103 inches. The primary coil is formed of 
No. 9 wire, and is about 80 feet in length. The condenser, made of tinfoil sepa- 
rated by oiled silk, has a surface in this larger apparatus of about 30 feet. Prof. 
Rogers referred to the very superb phenomena produced by the passage of the cur- 
