18 REPORT—1862. 
ical regions of the earth where tornadoes and cyclones occur, and those of Wilson 
in the last century. The facule are clearly shown, and seem to prove that the tro- 
pical regions of the sun are highly agitated, and that immense waves of luminous 
matter are thrown up, between which appear the dark cavities of the spots, whose 
sloping sides form the penumbrz, as explained by Wilson and others. Other ana- 
logies between solar spots and earthly storms were pointed out, and reference was 
made to the glimpses of the structure of the sun exhibited by Mr. Nasmyth as 
confirming the above views. 
On the Hindu Method of Calculating Eclipses. By W. Svotrtswoonn, F.R.S. 
The astronomy of the Hindus is contained in a series of works known by the 
general name of “ Siddhanta.”’ These have been composed at different times over 
a period of 2000 years. In them are some incidental allusions to the configurations 
of the heavenly bodies, by means of which Baily, Davis, and others have attempted 
to calculate the dates of some of the works. ‘There were two points to which the 
author drew particular attention, viz. the process of correction whereby the true 
longitudes were deduced from the mean, and the precession of the equinoxes. It 
had been noticed that the apsides, or points of slowest movement, and the positions 
of conjunction with the sun had proper motions. These were attributed to 
influences residing in the apsides and conjunctio:s respectively, and corrections 
due to each were accordingly devised. The undisturbed orbit was considered a 
circle, with the earth (E) in the centre, and upon it the centre of a smaller circle or 
epicycle moved with a uniform angular velocity equal, but opposice in direction, 
to that of the urdisturbed planet; so that M being the centre, ard m any given 
point on the epicycle, Mm always remained parallel to itself. If, then, at the apse 
or conjunction (according as the correction of one or the other was being calcu- 
lated) Mm was in a straight line with EM, the true position of the planet was 
conceived to be at the point where Em cut the undisturbed orbit. The radius, 
moreover, of the epicycle was variable, and its magnitudes at the odd and even 
quadrants being determined so as to satisfy observation, its intermediate variation 
was considered proportional to the sine of the mean anomaly. The precession of 
the equinoxes is an important element in Hindt astronomy, not only as a question 
of scientific accuracy, but also as marking an epoch in the history of discovery. It 
is an ascertained fact that their earlier writers, among the foremost of whom 
Brahmagupta may be mentioned, took no account of it whatever. The statement 
in the Surya Siddhanta, when divested of its obscure terminology, seems to amount 
to this, that the sidereal circle shifts on the zodiac with an oscillating motion, 
whose period is 7200 years, and whose maximum range is 27°. This gives an 
annual rate of 54”. 
On some Improved Celestial Planispheres. By C. J. Vita. 
Licut anp Heat. - 
On the Means of following the Small Divisions of the Scale regulating the 
Distances and Enlargement in the Solar Camera. By A. Cuavvet, F.R.S. 
The author, in a former paper, had proposed a new method for measuring both 
the distances of the negative and screen for any degree of enlargement of the image, 
by means of a scale or unity divided into 100 parts, and smaller fractions if possible. 
This scale being fixed on the table of the optical apparatus, an index connected with 
the frame holding the negative was brought exactly on any division of the scale 
which was indicating the proportion and distance of the image. This arrangement 
would be very complete and satisfactory if the scale were always long enough to be 
marked with divisions sufficiently conspicuous; but the shorter the focus of the 
object-glass, the smaller the divisions of the scale must be. In order to meet this 
difficulty, he has adopted the following plan :—He traces on the table an equilateral 
