REPORTS. 107 
theory of the existence of a time of more abundant rainfall, which he styles the 
pluvial period. The Beckford sand and local gravel beds are proved by the 
presence of sea shells of boreal type to be of marine formation and the abundance 
of mammalian remains in them, including Bos primigenius, Bos longifrons, 
and Bison priscus, and the bones of horses, red-deer and bears in the Cropthorne 
and Little Comberton drift help to give a picture of the fauna of the period when 
they were accumulated. Noimplements used by Palolithic man had as yet 
been discovered in the drift of our district, but a very fine polished flint axe 
turned up from the soil of Harvington, probably by the deeper penetration of the 
steam plough, testified to the existence of Neolithic man, who after a long inter- 
val of time succeeded his Paleolithic predecessor. A slate bracer in Mr. 
Ingram’s cabinet and described by Mr. Evans in his work on stone implements, 
may have protected the wrist of some Neolithic savage when he directed his 
arrow against the carnivorous creatures with which he disputed the dominion 
over the beasts of the field. Mr. Ingram agreed with Mr. James Geikie in 
considering the existence of the ice age of which our gravels afford indisputable 
evidence as due to the winters of our hemisphere occurring when the earth was 
in aphelion, or at its farthest distance from the sun, and not as they do now, 
when the earth is in perihelion, or nearest to the sun. A contemporary occur- 
rence of a maximum ellipticity of the earth’s orbit increasing the distance of our 
planet from the centre of heat by 8} millions of miles would necessarily intensify 
the cold. This astronomical phenomenon happening vast ages ago, and the slow 
dripping of stalagmite on cave deposits contemporary with a portion of our gravels 
all agree in corroborating the opinion warranted by the investigation of our 
drifts, that a period of long duration must have elapsed during their accumulation, 
disturbance, and redistribution. In fact, if astronomy affords us an insight into 
the immensity of space, geology offers to our contemplation an infinity of time.— 
March 5th, Mr. J. S. Slater read a paper on ‘“‘ The Reproduction of Ferns,’ illus- 
trated by specimens under the microscope. 
NOTTINGHAM LITERARY AND PHILOSOPHICAL SOCIETY.— 
Naturat Science Secrion.—February 28th.—Mr. Henry Hartnell read a 
paper on “The Mechanical Equivalent of Heat, and How it has been Deter- 
mined.” The terms ‘“‘ work” and “ energy,” as used by scientists, were explained. 
“ Work” was defined as the production of motion against resistance. ‘‘ Energy ” 
denotes simply the power of doing work. The principle of the conservation of 
energy was explained, and examples given of the different forms of energy. The 
conversion of work into heat, and the experimental methods by which the 
numerical relation between the quantity of heat and the quantity of work has been 
determined, were Jealt with. In establishing the convertibility of work into 
heat, Joule showed that to raise a pound of water 1°F. in temperature required 
the expenditure of as much energy as would raise a weight of one pound toa 
height of 772ft. Joule made experiments in the friction of solids and fluids, in 
magneto-electricity, and in the condensation of gases. In these experiments the 
mechanical energy of a suspended weight was transformed, by the friction of a 
paddle rotating in water, into heat, and the temperature of the water raised. 
Iron discs were rotated in contact with mercury. Mechanical energy was 
expended in generating electric currents by induction, which, in turn, were 
converted into heat, and by comparing the work expended with the heat produced 
the mechanical equivalent was deduced. The experiments in the condensation 
of gases gave approximate results. March 7th.—Mrs. Cowen read a paper on 
‘** A Ramble in the Inner Hebrides.” Starting from Glasgow, steamer was taken 
at Greenock, through the Kyles of Bute, along the lower part of Loch Fyne, 
through Crinan Canal, past the Slate Islands, to Oban and the Isle of Mull. At 
the latter place Loch na Keal and Craig Craiggen were visited. The geology of 
the Island ef Mull was described. The following botanical specimens were 
gathered:—Bog Myrtle, Drosera, Cotton Grass, and Bog Asphodel. The 
Island of Eigg was next visited, and the geology of the Scuir described. 
and illustrated by a photograph taken by one of the party. Specimens of the 
fossil conifer Pinites Eggensis were obtained in the conglomeratic beds beneath the 
pitchstone of the Scuir. From Higg the ramble led through the Sound of Sleat, 
to Raasay, Portree, and Gairloch, and the geology and scenery of the route were 
described. Mr. J. J. Harris Teall, M.A., F.G.S., gave a description of the 
microscopic structure of the pitchstone from the Seuir of Higg, of which the 
following is an abstract :—The matrix is of true pitchstone, with crystals of 
