SUGGESTIONS TO ASTRONOMERS. 369 
25. As the duration of the totality will be, m most places, ap- 
proximately known, the chronometer-bearer should be prepared to 
give about ten seconds’ notice to the observers of the re-appearance 
of light. At places near the north or south boundary this may be 
scarcely sufficient. Each observer should then remark,—first, whe- 
ther there is anything peculiar in the circumference of the moon ; 
secondly, whether the reappearance of the sun is heralded by any- 
thing like a twilight on the moon’s limb; thirdly, whether the co- 
rona disappears in separate parts ; fourthly, whether beads or strings 
are seen ; fifthly, whether the moon’s circumference is visible be- 
yond the sun’s visible limb; sixthly, whether the brilliancy of the 
sun’s limb is equal to or less than that of the portions of the disc 
immediately within it. The first appearance of white light should 
be noted by signal, as before. 
26. It would now be interesting for the naked-eye observer to 
remark, if possible, whether the light of the sun appears to sweep 
over the country ; whether there is any fluctuation of light on the 
ground, or on walls, &c.; and also whether dew or fog is formed. 
27. Any observations for intensity, polarization, &c. which were 
omitted. before the total obscuration, can now be made in a leisurely 
manner : and some measures of the interval between the cusps may 
be made with the sextant. 
28. During the remainder of the eclipse there will be little of 
interest to be done, except to repeat the observations of radiation, 
and to make any observations applying to the meteorological state 
of the atmosphere. The instant of termination of the eclipse (a 
phzenomenon which admits of accurate observation) should be noted. 
The actinometer-observations should be continued to a quarter of 
an hour after the last contact. 
Aprrnpix No. I. 
The following suggestions, applying specially to the observation 
of the beads or strings sometimes seen, are principally extracted 
from the “ Suggestions for the observation of the Annular Eclipse, 
Oct. 9, 1847,” in the Report of the Seventeenth Meeting of the 
British Association, Transactions of the Sections, p. 16. 
Whether the pomts of the cusps are rounded ? 
Whether in the neighbourhood of the cusp the limb either of 
the sun or moon appears distorted? Whether the beads appear 
steady or waying, disappearing and reappearmg? Whether they 
present any peculiar changes when viewed through differently- 
28 
