1854] ECLIPSE OF THE SUN, MAY 26th, 1854. 253 



They are thus situated: be seen through an ordinary telescope, provided the lenses are 



On the apices of the pelvic plates 5 well polished and perfectly clean. 



At the upper extremities of the upright sutures between Thc following a re the observations which it will be advisable 



the plates of the second series o . » f , ,.„„„i,:„*. ^,i;„,„ 



On the upper angles of the second series 5 to make during the progress of the approaching eclipse. 



Between the arms _5 These observations may be conveniently divided into 



I. Observations requiring instruments. 



There are thus twenty placed at the angles of the principal n observations wLioll may be made widl0ut i nstrU ments. 

 plates; but besides these, there are also several small ones 



among the supplementary plates on one side above mentioned. I. The observations requiring instruments may be again sub- 

 divided into two classes, which we may call Astronomical and 



' ~~ Physical. 



Eclipse of the Sxmi May 36th, 1S54. ^ obserrations lmder trje first c]ass ^J] be as Mow s ._ 



Extract from the Minutes of the Council of the Canadian ]sr ote t h e duration of the eclipse by ascertaining the exaci 



Institute. moment of the beginning and end, as denoted by a watch. 



, , ^, „ r „, , T . , . , . These epochs will be of no use in themselves, unless the watch's 



''Besolved, That Professors Chernman and Irving be appointed m ^ ^ rate have been accm . ate!y determined ; but if the watch 



a Committee to draw up instructions for general distribution be R t d one; fte difference between the epochs will give, 



relative to the approaching solar eclipse. ^ to]erab f e accuracy , the duration of the eclipse. At places 



where the eclipse is annular, there will be four epochs to be 



Report of the Committee appointed by the Council of the noted — the times of the two external contacts^ as in the case of 



Canadian Institute to draw up suggestions for observers of the partial eclipse^ and also the times of the two internal con- 



the Eclipse of the Sun on May 26th. tacts, corresponding to the beginning and end of the annularity. 



i- . To ascertain these times with any accuracy; there must be two 



The following recommendations are submitted by the com- obsei . vel . s _ one holdino- the watch and keeping his eyes fixed 

 mittee appointed by the Council of the Canadian Institute to the seColK js-hand ; the other looking at the point of the 

 draw up suggestions for observers of the approaching eclipse of sun wllere tbe contaCt fc expected. The signal should be given 

 the siin on May 26th. These suggestions are not intended to sbarp i y by a s i no -] e syllable. This observation may be made 

 be addressed to professed astronomers, but to those who, feeling without a telescope, but better with one. With a sextant, where 

 an interest in such subjects, would gladly have those circum- the ec]i is tia]; the distance between the cusps may be re- 

 stances pointed out on which they should fix their attention, as peate dly measured about the time of the greatest obscuration ; 

 giving them the means of increasing the recorded data, or as and where the ecli j s annmar) several measures of the breadth 

 likely to be of special interest to themselves. of the annulus raay be made in its narrowest part : in both cases 



The eclipse being, under the most favorable circumstances, notin g the time of each observation. It will also be interesting 



only annular, the peculiar phenomena of a total eclipse will not to obtain a measure of the moon's apparent diameter, where the 



be 'seen, viz., the corona, and the rose-colored flames or promi- ecU P se is annular. In consequence of the irradiation of the sun s 



nences. The corona is never seen till an instant or two after the ]i g ht , the measure thus obtained may be expected to be less than 



total obscuration has begun. It is a ring of light, or halo, sur- the calculated apparent diameter. 



rounding the sun, within which have generally been seen certain The f n ow ; no - are the points to which an observer who has 



red flames, as it were bursting out from the side of the moon, tbe opportunity 3 of usino- a telescope should especially direct his 



very variable both in shape and size. Of these latter we cannot atte ntion. An ordinary telescope will be sufficient for these 



expect to see anything during the approaching eclipse, nor of .the purposeS) pr0 vided that it is fitted with coloured glasses of various 



corona directly. Indirectly, however, we may probably meet sbades t0 enable the e to bear the sun's light, 

 with proof of its existence, and that in a way which will tend to 



confirm the theory of its appearance; which is this— The sun is 1- The serrated or jagged edge of the moons disc may be 



supposed to be surrounded by an atmosphere like our own, non- seen with a low magnifying power, as she moves over the sun s 



luminous but capable of reflecting light, which would produce face. 



to us the same appearance as if the sun's disc were surrounded 2. When about half the sun's diameter is eclipsed, the ob- 



by a faintly luminous ring. In consequence, however, of the server should carefully endeavour to detect the portion of the 



general brightness of the sky produced by the dispersion of the moon's disc exterior to the sun ; and he should especially notice 



sun's direct light by our own atmosphere, this ring is not gene- whether that portion of the external surface of the moon which 



rally visible. In a total eclipse, the brightness of the sky is so i s i ose to the sun is seen with sensibly greater distinctness than 



far reduced in the immediate neighbourhood of the sun that the p a rts at a oreater distance. It may be well here to repeat the 



ring becomes visible, and constitutes the corona. In a partial warning, that there will be no chance of this observation being 



eclipse the sky is still too bright to admit of our seeing this ring successfully made, unless the lenses of the telescope are well 



as a corona, but its illumination is strong enough to render visible cleaned. 



the part of the moon exterior to the sun's disc as a dark body on „_, . _. _ ,. , , -, . ■•.j„_ + „ „_ 



v. • i . „ , u t , ., , , • J j- 3. The cusps should be attentively watched, in order to as- 



a brio-ht ground, the part nearer the sun's edo-e beine- more dis- . • ■ uua H a . - ' , „t- f t.._ 



tinctly seen than that more remote. This is in accordance with eertaln whetl f v tbe ? r ™ ^ a " d ^ ^ ' ' 



observations which have been already made; and it will, there- at an 3' tlme ^ e 7 beoome bUmted or lrre g ular - 



fore, be an object of interest to look for the portion of the 4. Where the eclipse is annular, the phenomena known as 



moon's disc exterior to that of the sun. It will probably be "Bailey's beads" may be looked for. When the western limb 



visible when about half the sun's diameter is obscured, and may of the moon is leaving the western limb of the sun, it appeal's 

 3 



