TRANSACTIONS OF THE SECTIONS. 
17 
ij ifi duration only is required, a common watch showing seconds will suffice for 
ikc purpose. 
'If possible, by means of a graduated pearl scale or other equivalent means, the 
nadth of the narrowest part of the annulus should be measured several times about 
itiniiidle of the time of the annular appearance, as well as it can be estimated. 
'Atotkrplaccs the eclipse will not be completely annular, and here the prin- 
fil object must be to make several raeaburi’s of the distance between the cusps 
Mttbe time when that distance is smallest. This measure may probably be made 
7 B«n8 of a graduated pearl scale, or by means of a divided object-glass applied 
ifwDt of the object-glass of the telescope: or by the use of a common sextant. 
“VI. Asm the particular points of physical interest to which attention should be 
•ated, tli^ may be staled as follows 
“I. It will be desirable in general to notice the fact of tlie appearance of what are 
wminital ‘ beads ' and 'threads' by the late Mr. Daily and others, just before 
^tfhrthe cumpletion of the annulus. 
[FordetaiUof older observations the observer should constilt Ast. Soc. McraouB, 
i. U2-146; X. 10-17, 33-38. The beads were observed by Mr. Daily, 
ib. t. 310, in 1842, when they were not seen by Mr. Airy, ib. x. 218- They 
vrereubserved by Prof. Henderson at Edinburgh. A*t. Soc.Notices, v. 186.J 
Whether in the neighbourhood of the cusp the limb cither of the sun or moon 
^ira distorted? Wliether the beads appear sfcflrfy or wanng, disappearing and 
faring, 8:c. f [See the observations of Mr. Caldecott at Trevandcum, Aat. Soc. 
Whetlicr they present any peculiar changes when viewed through 
^rsatly coloured glasses, the observer alternating the colours, which should be as 
^niilar as possible, such os red and green. [Sec SiUiman’s .Tournal, Jan. 1842.3 
p ^dher they are seen when the eclipse is projected on a Screen ? [In this 
w mf. Chcvdlicr saw none when others with coloured glasses saw them. Ast. 
"^'Notices, r. 186.] 
The drawing out of the beads into lkread$ when very near junction ; and 
,,, travp^r and changp, and the number of them. [See Ast. Soc. Mem., 
and changing, ib. x. 12, 13 ; not seen in 1842 by Mr. Daily, 
i«£m before and after the formation of the threads the moon’s dark disc 
towards the point of contact? [Thia was observed, ib. x. 29, ami wavy 
I. 12,14,30.] . .. 
^ • be beads are ascribed by some to lunar mountains. What mountains exist 
part of the limb? [Sec Ast. Soc. Mem., x. 9, 16, 30-36.] 
*, • intervals of time elapsed between the first and last complete con- 
£,7 tlist of the first and last, formation of beads or other irregularities m or 
cusps, should be determined. The difference of the rimes being all that is 
“y. a good ordinary’ watch will be sufficient. [The remarkable fact of a rec«r- 
observed by Mr. Airy in 1842, and his eitplanatiou of it, should be 
“« Ast. Soc. Notices, V. 296.3 ... 
mwarra should be taken of the apjiarent diameter of tiie 
i w>»ch may be expected to be greatly less than 
’ 9 . oT the sun's light. , _ , 
noticed whether any external Itimiaous arch ib formed over tne 
•.j . the CU«nii a — a uAi»«* fl SPOafatlOD, 
^«lwT ^ remarlcB of Prof. Powell an explanation of a 
“y whereby, by georaeUical 
S ^ “certained to wdthin a minute of time, the exact period 
e:rcatest phase-and the end : also he 
of the sun's disc which will be “^^red by the 
k»theUtfcf '^’i^^rvationh were illustrated by a projection of the eclipse of Oct- 9 
city is beyond the northern limit within which the 
1847 ^nular. ^ 
c 
