, 
330 
eminently satisfactory, and that there was no perceptible 
loss of illuminating power. Experiments on this point, 
however, and also upon the arrangements that will best 
enable the heating gas to be turned to account, are still 
in progress, and will afford ground for further notice in 
due time. 
The furnace and retorts which are at work at Battersea 
are very compact, occupying about the space of an ordi- 
nary well-packed steam engine of 20 or 30 horse power. 
These retorts however are only in use for about two hours 
out of the twenty-four to supply the works with illumina- 
tion, and it is estimated that they would be quite large 
enough to supply illuminating gas for the consumption of 
a small town of about 4,000 inhabitants. As regards the 
most important bearing of saving of manual labour it is 
found to amount to dispensing with the services of 29 
labourers out of every 30 who are required in the old pro- 
cess of coal distillation. The charge of coke and iron 
which is now in the retorts yielding the gas at Battersea 
has not been changed, or renewed, for several weeks. 
The iron in the retorts is in the form of old chain, for the 
convenience of withdrawal, and seems to cover itself with 
thin black scales. The carbon in the interior of the 
retort is removed entirely by the gas as it is gradually 
converted in the process of manufacture into carbonic 
acid and carbonic oxide. 
It may, perhaps, be well to remark that a process for 
the manufacture of “water gas” was presented by M. 
Gillard some fourteen years ago, in which superheated 
steam was decomposed in retorts by the action of incan- 
descent charcoal ; the carbonic acid, so formed, issued 
from the retort with the hydrogen, and was afterwards 
removed in aspecial purifier. Lighting power was secured 
by heating platinum wire in the flame. The distinctive 
features of Mr. Ruck’s process are—the decomposition of 
the superheated flame by coke and iron, which remain 
long periods in the retorts without change ; the removal 
of sulphur products by oxide of iron ; and the carbonising 
for illumination by passing the hydrogen through rectified 
petroleum. 
HUNTERIAN LECTURES BY PROF. FLOWER 
Lectures I, II, III. 
I* 
considering the various formations which compose 
the earth’s crust, it is unnecessary, whilst speaking of 
the mammaiia, to refer to rocks lower than those of the 
secondary formation, for no palzeozoic mammals are known. 
Respecting the value of palzontology in supporting or 
disproving the various theories at present in vogue re- 
garding the origin of life, the details of the course will 
supply evidence of value. The amount of “the imper- 
fection of the geological record” will be demonstrated in 
the classes considered. The extreme unlikelihood of any 
aérial animals being preserved in the fossil state is scarcely 
realised by many, nor is the smallness of the extent of | 
the surface of the earth which has been examined. An 
accidental discovery like that in the upper oolite, of an 
extremely small deposit containing numerous marsupial 
remains, has done more to throw light on the subject 
than many more painstaking researches over larger fields. 
These facts being taken into consideration, it is clear that 
if it can be shown that the examination of fessil 1emains 
indicates only a tende: cy towards the filling of the gaps 
between existing groups, the tendency will be strongly in 
favuur of evolution ; but if it brings to light nothing but 
types which are entirely new, the doctrine of special crea- 
tions will be supported. Prof. Huxley has been able to show 
. many of the transitions between reptiles and birds, and 
Prof. Marsh’s new discovery of (dontornis is an im- 
portant addition. It is among mammalia that in the pre- 
‘sent state of our knowledge there are the greatest gaps. 
The relations of the Cheiroptera are indeterminable, and | 
NATURE wre: 
ay 
so are those of the Edentata ; not much is known of the © 
Cetacea as regards their affinities, though they may be 
near the seals on the other hand. The Ungulata constitute 
a group in which the considerable gaps between existing 
types are almost completely removed by the study of 
fossil forms. 
Pliocene, Equidee abounded in America as well as in 
the Old World. Tapirs and Rhinoceroses were equally 
abundant ; these are the remnants of a large group which 
is probably becoming extinct, as it is indicated by the 
fact that the species are becoming less numerous. A little 
further back we find Hipparion with rudimentary side toes. 
Taking first the Rerissodactylata, in the — 
In the Miocene and upper Eocene, Anchitherium and 
Palzotherium represent the group, though the latter is 
peculiar in its teeth. Fossil Rhinoceroses have larger 
teeth and no horn, some pdssess incisors, and the other 
teeth less specialised. The Tapir stands much by itself, 
and an ancient type containing Lophiodon and Hyraco- 
therium seems to be now unrepresented. Again, among 
the Artiodactylates, Cheropotamus and Hyopotamus as far 
back as the Eocene are the most generalised, and from 
them as we ascend in the series the differentiation towards 
existing types becomes more and more evident. Among 
these later forms the North American Oveodon, which has 
been obtainedin such great numbers, tends to the ruminants, 
but possessed upper incisors and canines. The Miocene 
of France and Germany affords very similar evidence. 
It is also interesting to note that the further we go back, 
the more do the individuals of the Perissodactylate group 
approach the Artiodactylates, but as yet no connecting — 
link has been obtained. The Proboscidia, animals first 
appearing in the Miocene, approach in the older forms to 
the Ungulata, and Prof. Marsh’s newly discovered Dino- 
ceras seems to help to fill the gap. 
In reviewing the various strata which are found to con- 
tain remains of mammalia, those of the quaternary or 
post-pliocene period are rich in species not far removed 
from existing forms. In most countries where limestone 
rocks exist, caverns are found containing large numbers 
of bones, such as those of Kirkdale, Liege, and Gibraltar, 
the last having been lately explored by Mr. Busk. Those 
of the Wellington Valley in Australia have afforded nu- 
merous remains of marsupials, showing that those animals 
have been located there for a considerable period. Again ~ 
from the Pampas of South America many of the valuable 
skeletons which enrich the collection of the College of 
Surgeons have been obtained. The Miocene formation — 
is particularly interesting from the richness of its fauna. 
Dinotherium and Mastodon being obtained in South 
France, as well as at Pikermé in Greece, where they are 
associated with A/7pparion, the giraffe and others. Belong- 
ing to the same formation are the strata of the Siwalik 
Hills of India, which abound in hoofed animals, and 
have been so well worked out by Dr. Falconer. The 
peculiar mammalia of the territory of Nebraska, at the 
foot of the Rocky Mountains, belongs to the same age. 
In the Eocene period lived the animals so fully described 
by Cuvier, Palgotherium, Anoplotherium, &c. Besides 
in the Paris basin, similar strata occur at Hordwell, in 
Hants, and at Binstead, Bembridge, and Headon, in the 
Isle of Wight. In the Lendon Clay of Sheppey Hyraco- 
therium and Lodhiod mare found. ~ 
Early in this century, it was supposed that mammalia 
were not present in the secondary rocks ; but this was 
shown to be incorrect. In 1847, Prof. Pheninger dis- 
covered in sone Triassic sand he was sifting a minute 
tooth with double fangs, probably belonging to some mar-— 
supial anima’, which he named Mzcrolestes. Prof. Owen 
considers it to be related to MM/yrmecobius. Similar’ 
teeth from the Rhaetic beds have been discovered 
by Mr. C. Moore, of Bath. An equally minute” 
Triassic tooth was found by Mr. Boyd Dawkins at 
Watchet, in Somersetshire, and from its slight resem-" 
b'ance to that of A/ypsiprymnus it has beea named> 
