Guntoor is quite an important place, being the centre of a large cotton trade. This cotton comes mostly from Nizzam, and is shipped to Europe from the ports of Cocanada and Masulipatam. Several French merchants, with their families, live at Guntoor; they are descended, generally speaking, from those ancient and numerous families which in former times were the glory of our beautiful Indian colonies.
My observatory was at the residence of M. Jules Lefaucheur, who was so kind as to place at my disposal all the first story of his house, which is in the highest and best part of the city. The rooms of this first story communicated with a large terrace, upon which I erected a temporary structure suitable for the observations intended.
The instruments were several achromatic lenses of six inches aperture, and a Foucault telescope of twenty-one centimetres. The former were all mounted upon one stand. The general movement was given by a mechanism constructed by Messrs. Brunner Bros., which enabled one to follow the sun by a simple rotation.
The apparatus was furnished with finders of two and two and three quarter inches aperture, which were themselves good astronomical glasses. In spectral analysis, these finders have a peculiar importance; for by means of them the precise point of the object under examination is known, to which the slit of the spectroscope in the principal telescope is directed. It is therefore necessary that the cross-wires, or in general the sights placed in the field of the finder, should correspond with great exactness with the slit of the spectral apparatus, and I had, of course, taken great care to secure this essential point. Special micrometers were also provided, to measure rapidly the height and angle of position of the protuberances. As for the spectroscopes, I had chosen them of different magnifying powers, so as to answer to the different requirements of the various phenomena. Finally, the apparatus carried, at the eye-piece end, screens of black cloth, forming a dark chamber, in order to preserve the sensibility of the eye.
Besides these instruments, intended for the principal observations, I had brought a full set of very delicate thermometers, made with great skill by M. Baudin; also some portable spy-glasses, hygrometers, barometers, etc. Thus I was able to turn to account the kindness of MM. Jules, Arthur, and William Lefaucheur, who offered their services for the subsidiary work. M. Jules, who is a good draughtsman, undertook to sketch the eclipse. An excellent telescope, of three inches aperture, furnished with cross-wires, was assigned to his use; he practised with it the representation of the expected phenomena by means of artificial imitations of eclipses. The thermometric observations were given to M. Arthur, who was also directed to ascertain the brilliancy of the protuberances and of the corona at the moment of totality, by a very simple photometric process.
I was assisted in my own operations by M. Redier, a young subaltern, whom the commander of the steamer L'Imperatrice had supplied to me. The services of M. Redier, who has excellent observing qualities, were very useful to me.
The time which remained before the eclipse was employed in preliminary study and practice, which served to familiarize us with the handling of our instruments, and suggested to me various improvements in them.
The day approached, but the weather did not promise to be favorable. It had rained for some time all along the coast. These rains were considered as extraordinary and exceptional. Fortunately, they moderated gradually before the 18th; and on that day the sun rose unclouded, and dimmed only by a mist out of which it soon passed; and at the time when our telescopes showed us that the eclipse began, it was shining with its full splendor.
Every one was at his post, and the observations immediately commenced. During the first phases some thin vapors passed before the sun, which interfered somewhat with the thermometric measurements; but, as the moment of totality approached, the sky became sufficiently clear.