408 
comet is probably well known to many, who will recollect 
the form of Donati’s comet. Although, as you know, that 
comet appeared only about ten years ago, unfortunately 
it came too early for us to learnanything about it by 
means of the spectroscope, We have, first of all, an 
extremely bright nucleus ; then a kind of semilune of 
greater brilliancy than the rest of the head , then what is 
called the coma, and the tail. The question which the 
spectroscope had to put to the comet was—of what is the 
nucleus composed, and of whatis the tail composed. Prof. 
Donati, and Mr. Huggins especially, to whom we owe so 
much for his work in this direction, has made some ob- 
servations ontwo small comets—Iam sorry they were not 
larger—with considerable success. He found that in the 
comets he examined, the head gave out a light which very 
strongly indeed resembled the spectrum of carbon vapour. 
The spectrum of carbon taken with the spark in olive oil 
and in olefiant gas differs slightly; the spectrum as 
obtained from the latter consists of three bands or waves 
of light, which commence tolerably bright and sharply on 
the red side, and become gradually fainter towards the 
more refrangible side. These bands are severally situated 
in the beginning of the green, in the true green, and in 
the blue portions of the spectrum. Mr. Huggins has also 
observed the spectrum of Encke’s comet,and has confirmed 
the result that he previously obtained, viz., that the spec- 
trum of the comet is identical with the spectrum of carbon, 
as taken in ahydrocarbon. I should like to draw your 
attention, if there were time, to the way in which these 
spectra of the carbon spark taken in oil and in olefiant gas, 
differ. 
I have not yet completed all I have to say on the 
subject of radiation. If, as we have already seen, we take 
a tube containing incandescent hydrogen and passa 
series of intense electric sparks through it, we see that it 
gives out a red light, which may remind you of some 
other specimens of radiation which is supplied us by the 
skies. I allude to the red prominences which are seen 
around the sun, not in ordinary times, but when the sun 
is eclipsed. This representation gives you a good idea 
of what really is seen when the sun is eclipsed, when 
we have as it were a black sun instead of a bright one, 
which is really nothing, but the body of the moon. 
Around this we have a ring of light, which is called the 
corona, and here and there in this corona we have what 
are called red flames and red prominences. These red 
prominences have also on closer observation been found 
to be only local aggregations or heapings up of a red 
layer which surrounds the outer edge of the sun. Here, 
then, it was quite possible that if the newly invented 
spectroscope were set to question these things, we should 
see at once whether they were solid or liquid, or whether 
they were gaseous or vaporous. If we got a continuous 
spectrum from these red things, we should know that they 
were solid, or liquid, or densely gaseous. If, on the 
contrary, we got a bright line spectrum we should know 
we were dealing with a gasor vapour. You also see that, 
as the light is red, the chances were that they were not 
solid or liquid, and then you further see that if the things 
do consist of a light which does give us lines, a deter- 
mination of the exact position of the lines, and a com- 
parison of these positions with those of hydrogen, 
sodium, magnesium, barium, or anything else, would 
teach us what these things were. 
J. NORMAN LOCKYER 
PROF. FLOWERS HUNTERIAN LECTURES 
LECTURES XIII. XIV. XV. 
[A PIRIDA:, The geographical distribution of the exist- 
ing members of this small order is very peculiar, they 
being confined tothe Malay Peninsula, Sumatra, and most 
of South America. Lund has found their remains in the 
Post-pleistocene caves of Brazil; they have also been 
NATURE 
obtained in abundance from similar deposits in North — 
America, and these can hardly be distinguished from those 
at present existing ; in China likewise Pleistocene Tapir’s — 
-welldeveloped ; 7. dairdi is 
_mouth, in the Isle of Wight, and in Hampshire. S 
 ¥ 
[Mar. ay, 1873 
teeth have been found. In Europe during the same time ~ 
they do not seem to have existed, although Elephants 
and Rhinoceroses were abundant. In the Pliocene and 
Miocene, Tapirs are not unfrequently met with at Ep 
sheim, Auvergne, and elsewhere ; perhaps they originated 
in Europe, and thence spread east into Asia, and on to 
America. Respecting their anatomical peculiarities, the 
teeth are forty-two in number, the anterior lower premolar — 
being absent ; the molars and premolars are much alike, — 
forming a uniform series ; the incisors are smaller than 
the canines, they have a small cingulum. The molars © 
are a modification of those of Lophiodon, the transverse — 
ridges are very prominent, and the cusp of the cingulum ~ 
is less developed. The lower possess two simple trans- 
verse ridges, as in Lophiodon, but the last in the series 
wants the extra back lobe. The anterior nares are very 
open and the orbit is incomplete behind. There are four 
toes on the front foot, and three behind; the radius and 
ulna as well as the tibia and fibia are quite separate and 
eculiarin that the meseth- — 
moid cartilage is well ossified, and the maxillaries are 
specially developed upwards to support it. 
‘To 
The Paleotheride occur in the Upper Eocene only, 
they were first found at Montmartre and worked out by 
Cuvier ; since that time they have been obtained from 
many parts of France, the Bembridge clay, near Yar- 
genera have been separated off, and about a dozen species, — 
from the size of a small rhinoceros downwards. In ~ 
general aspect they must have been tapir-like. The 
maxilla curved downwards in front as in the tapirs ; the — 
orbital and temporal fossze were also united, and there ~ 
were large anterior osseous nares ; the feet were much 
like those of the tapir, though they were more specialis 
in wanting the fifth toe to the manus. The typical forty-— 
four teeth were present ; the incisors were more uniform 
than in the tapirs; the first pre-molar was rather rud 
mentary, the others formed a uniform series with t 
molars, which were wider than from before backwa 
much pressed together, and with short crowns. They 
be shown to have been developed on the type of Lophi- 
odon, the outer wall bulging inwards, opposite the outer 
cusps, instead of outwards, giving the earliest indication 
of the lunate type of tooth; the transverse ridges were — 
normal, and the internal cusps were slightly cut off from 
them, turning backwards as the rudiments of the posterior 
semilunes. The lower teeth presented a peculiarity here 
first noticed, each being formed by a double crescent, 
quite different from those of the tapir. The last lower — 
molar had a third crescent behind as in Lophiodon and ~ 
the Artiodactylata, but, different from the latter, in the 
corresponding milk tooth not presenting it. Padaplo- 
theriumt was a smaller and earlier genus described by 
Owen from Hordle. In the upper jaw the first premolar — 
was missing, and the corresponding lower one soon lost; — 
the others were comparatively simple. The remains are — 
very abundant, the feet were as in Palzotherium. Gervais — 
has given the name Propal@otherium to a few teeth of 
another early form, intermediate between Lophiodon and 
Paleotherium. <Aychitherium was an American form 
closely allied to the strictly European Palzotheride, 
Rhinocerotide are at present found in Africa and South ~ 
Asia only ; they belong to three types, the African two-— 
horned, non-scutellated ; the Asiatic two-horned, and the 
Asiatic single-horned. The extinct members were nu-— 
merous ; four species existed in England. They did not — 
appear before the Miocene epoch ; many are found in 
America, but not above the Pliocene period. The exist- 
ing genera have peculiarities in their incisor dentition ; 
these teeth are quite absent in the African, and two above ~ 
as well as below in the Indian species ; when they are 
