August 4, 1881] 



NATURE 



309 

 f 



comets, this band might be photographed in their 

 spectrum. 



Accordingly at the first attempt a photograph of the 

 nucleus and part of the envelopes was obtained in seven- 

 teen minutes, on the night of June 24, through breaks in 

 the clouds. On succeeding occasions, when an exposure 

 of 162 minutes was given, the tail impressed itself to an 

 extent of nearly ten degrees in length. 



I next tried by interposing a direct-vision prism between 

 the sensitive plate and the object-glass to secure a photo- 

 graph which would show the continuous spectrum of the 

 nucleus and the banded spectrum of the coma. After 

 an exposure of eighty-three minutes a strong picture of 

 the spectrum of the nucleus, coma, and part of the tail 

 was obtained, but the banded spectrum was overpowered 

 by the continuous spectrum. 



I then; applied the two-prism spectroscope used for 

 s'ellar spectrum photography, anticipating that, although 

 the diminution of light would be serious after passing 

 through the slit, two prisms, and two object-glasses, yet 

 the advantage of being able to have a juxtaposed com- 

 parison-spectrum would make the attempt desirable, and, 

 moreover, the continuous spectrum being more weakened 

 than the banded by the increased dispersion, the latter 

 would become more distinct. 



Three photographs of the comet's spectrum have been 

 taken with this arrangement with exposures of 180 

 minutes, 196 minutes, and 228 minutes, and with a com- 

 parison spectrum on each. The continuous spectrum of 

 the nucleus was plainly seen while the photography was 

 in progress. It will take some time to reduce and digcuss 

 these photographs and prepare the auxiliary photographs 

 which will be necessary for their interpretation. For the 

 piesent it suffices to say that the most striking feature is 

 a heavy band above H which is divisible into lines, and 

 in addition two faint bands, one between G and //, and 

 another between h and H. I was very careful to stop the 

 exposures before dawn^ fearing that the spectrum of 

 daylight might become superposed on the cometary 

 spectrum. 



It would seem that these photographs strengthen the 

 hypothesis of the presence of carbon in comets, but a 

 series of comparisons will be necessary, and it is not im- 

 probable that a part of the spectrum may be due to other 

 elements. HENRY Draper 



271, Madison Avenue, New York 



My first view 'of the comet was on June 25, when it 

 appeared through a momentary opening in the clouds, 

 with a nucleus that, in size and brightness, seemed to 

 equal Venus at her best. The tail, immediately at its 

 commencement, was exceedingly bright also, but I could 

 see no more of it then, nor at a second view, also mo- 

 mentary, when little more than the head was visible. 

 Notwithstanding the immense development of tail shown 

 by the great comet of 1 86 1 it could not compare for an 

 instant in brightness with the nucleus of the present one 

 as I saw it on June 25. 



On June 27 I again observed it wonderfully waned in 

 light, with a tail plainly traceable for ten degrees, and 

 pointing directly to the Pole. The tail was slightly curved 

 to the right ; that is, it was convex to the apparent east, 

 or on the preceding side, and was brightest and best 

 developed on that side. There was no time for observa- 

 tion with the telescope when the clou Is shut up the skies 

 for the remainder of the night. 



On the next night, the 28th, I got a view with the tele- 

 scope, and by an observation, which was much interfered 

 with by clouds, I made out the position to be, in Right 

 Ascension, 5h. 58m. 44s., and in Declination 63' 12' 53", at 

 i2h. I5tn. Greenwich mean time. The comet was pro- 

 gressively waning, but the tail seemed still about 10° 

 long, and pointed to the Polar star. The nucleus, though 

 growing smaller, was still exceedingly brilliant, and as 



large as a star of the first magnitude. The direction o" 

 the tail did not differ very much from the comet's appa 

 rent course, and seemed LO)icavc to it, contrary to what is 

 usually observed wqth other comets. With a power of 126 

 on a 4.i-inch achromatic I saw a curve of light extending 

 like wings on each side of the head, and outside, with a 

 dark space between them, appeared a large envel.:>ping 

 curve of inferior brightness. I fancied at times that I 

 could discern a very faint third envelope outside all. 

 These curves extended farther in the direction of the tail 

 on KMt following side than on the other, though it was on 

 the latter or preceding side that the tail showed the best 

 definition. 



On July 8 the comet seemed much diminished in light 

 and magnitude, though the nucleus was still brightly 

 stellar. 1 could now see only the inner light-curve ex- 

 tending on both sides of the comet's head, and through 

 it on the following side I distinctly observed a small star 

 shining, as it would appear, with undiminished brightness. 

 The preceding side of the tail was still brighter and better 

 defined than the following. I made the comet's position 

 at i4h. G.M.T. =-- Right Ascension 7h. 49m. 38s, and 

 Declination 79° 27' 21". 



On July II it was still further diminished, and in the 

 bright moonlight there was no longer any light-curve 

 traceable in my telescope. The nucleus however con- 

 tinued remarkably bright and star-like, and there was an 

 extensive nebulosity round it. The tail might be traced 

 by the naked eye three or four degrees. I had on this 

 night a very satisfactory micrometrical observation, but I 

 have not as yet been able to perfectly identify the star of 

 comparison. The calculated light of the comet was 

 scarce more than a tenth of what it was on June 22. It 

 is now fast receding out of naked-eye riew, and of little 

 interest except for marking its position. This on July 20, 

 at I2h. 20m. G.M.T.. I made to be iih. 17m. 47s. in 

 R.A., and 82° 9' 2" in Declination. 



Schaeberle's comet i^ now well in view, and would be 

 visible to the naked eye only for the brightness of the 

 sky where it is moving. The weakest binocular is suffi- 

 cient to show it, and it is rapidly gaining in brightness. 

 On the 27th inst. it appeared to me with a stellar nucleus 

 and a tail visible for about half a degree. I made its 

 position at i4h. 15m. G M.T. = 6h. 14m. 41s. R. Ascen- 

 sion, and 43' 59' 10" in Declination. The observation 

 was difficult owing to the brightness of the sky and to 

 clouds. 



Millbroo'-, Tuam, July 28 J. Birmingham 



A POPULAR ACCOUNT OF CHAMELEONS'' 



THE animal to which I propose especially to direct 

 your attention to-day is one which has been the 

 subject of many observations, and has inspired great 

 interest from the most ancient times. 



Its name " chamaeleon " is derived from two Greek 

 words signifying " Ground-lion," a name singularly inap- 

 propriate, since it is one of those creatures w^hich are 

 specially fitted by their organisation to live on trees, and 

 which aVe comparatively ill at ease when on the surface of 

 the earth. 



It is by no means surprising however that this creature 

 should have attracted the attention it has attracted, such 

 is the singularity of its appearance and the peculiarities 

 of its habits and properties. Neither is it surprising that 

 it should have occasioned many errors and superstitions 

 when we consider the erroneous beliefs current amongst 

 ourselves with respect to our own toads and slow-worms, 



efts, &c. J rl,- \ 



Aristotle was acquainted (as was to be expected ot tiimj 



with the singular motions of its eyes, but even he fell into 



some curious mistakes respecting it, and he tells us that 



■ Lecture delivered at the Zoilgical Gardens on July 28, 1881, by St 

 George Mivart, F.R.S. 



