484 
loose it retarded it very much. From this follows the 
practical truth, that we can produce a very different 
effect by the same number of clothes according to their 
make. 
“ Generally our clothing has been considered as an ap- 
paratus for keeping the air from us. This conception is 
utterly erroneous, and we can bear no garment which 
does not allow of a continual ventilation of our surface. 
Just those textures which are most permeable to the air 
keep us warmest. I have examined different materials for 
their permeability to air, and taking the permeability of 
air passing through flannel as 1oo, linen allowed 58, silk 
40, buckskin 58, chamois 51, kid 1 part of air to pass 
through them. If the above-stated notion were correct, 
kid would keep us I00 times, chamois warmer by half, 
than flannel, and so on, while everyone knows) that it is 
quite the reverse.” 
With reference to Fur the author says :—“A fur 
is so arranged that its fine hair projecting into the 
air intercepts all the heat which flows from the surface of 
the body by radiation and conduction, and distributes 
this heat through the air which circulates between the 
single hair-cylinders. Thus the air, however cold it may 
be, reaches the nerves of our skin as a warmed air. 
Furred animals in winter, when touched superficially, give 
a very cold sensation ; it is only near the skin that their 
hair feels warm. Ina severe cold, certainly little of our 
animal heat comes as far as the points of the hair, from 
which it would escape by radiation or conduction, as the 
current of air in the fur cools the hair from its points 
towards its roots, and a severe cold penetrates only a little 
farther into the fur, without reaching the skin of the same. 
This can take place only at an exceedingly low tempera- 
ture, or when avery cold air is in violent motion. Ina 
well-furred animal the changes of temperature in the 
surrounding air only change the latitudes at the cold and 
warm zones in the fur ; the place where the temperature 
of the body and the air equalise each other, moves be- 
tween the roots and points of the hair, and for this reason 
a furred animal is not warmer in summer than in winter. 
In summer its heat leaves at the points, in winter near the 
roots of the hair.” 
Fournal of the Proceedings and Annual Report of the 
Winchester and Hampshire Scientific and Literary 
Society, vol. i., part ii, 1871-2 (Winchester: Warren 
and Son, 1873). 
WE are glad to see from the Third Annual Report of this 
Society that it continues prosperous, the number of mem- 
bers being, in 1872, 105. We hope good use will be made 
of the valuable herbarium of flowering plants, ferns, 
lichens, &c., collected and arranged by the late Mr. Hill, 
which has come into the possession of the society, through 
the generosity of the Mayor, Mr. R. P. Forder, and the 
President. The present part of the journal contains a 
number of papers, literary and scientitic, read at various 
meetings of the society. The principal one is the Intro- 
ductory Address delivered at the commencement of the 
third session, by the Rev. Canon Kingsley, on “ Bio- 
Geology—the science which treats of the distribution of 
plants and animals over the globe, and the causes of that 
distribution.” The address is an eloquent one, it can 
easily be imagined, shows extensive knowledge and great 
shrewdness, and contains many valuable hints both to 
young and old naturalists. Most of the other papers are 
also by clergymen, the principal ones being the follow- 
ing :—“ On the Dawn of Thought in Greece,” by the 
Rev. W. Awdry ; “On the Metamorphosis of Lepidop- 
tera,” by Mr. J. Pamplin; “the Planet Jupiter,” by the 
Rev. E. Firmstone, in which the author gives many inte- 
resting facts and speculations as to the condition of that 
planet ; “‘ Vesuvius previous to and during the Eruption 
of 1872,” by the Rev. C. A. Johns, in which the author 
describes an ascent he made shortly before the last erup- 
NATURE 
[Oct. 9, 1873 
tion, and appends a condensed abstract of Palmieri’s 
account of the eruption. Appended to the journal is a 
valuable list of 315 works on the Geology, Mineralogy, 
and Palzontology of the Hampshire Basin, compiled by - 
Mr, William Whitaker, of the Geological Survey. 
= 
LETTERS TO THE EDITOR 1 
[The Editor does not hold himself responsible for opinions expressed 
by his correspondents. No notice is taken of anonymous 
communications. | 
Wyville Thomson and the Ventriculide 
I Trust that you will afford me a little space fora few 
remarks upon some passages in Prof. Wyville-Thomson’s book, 
the ‘‘ Depths of the Sea,” which, owing to many engagements, 
has only just come into myhands. So earnest a labourer in the 
wide field of truth will not, I hope, deem me discourteous if I 
point out one corner where his feet have slipped ; and if it be — 
objected that, after all, it is only in a small spot, the learned — 
Professor will, I am sure, agree with the answer that, even in 
the smallest steps towards truth, attainable accuracy is im- 
portant. 
In 1847-48 my father published a series of papers in the 
“Annals and Magazine of Natural History,” which were after- 
wards collected into a volume, on the ‘‘ Ventriculidze of the 
chalk, their microscopic structure, affinities, and classification.” 
This work, which still remains, I believe, the authority on its 
subject, introduced order and classification where before all was 
confusion, expressly founding these upon two guiding principles 
of anatomy, the existence of which had been proved by searching 
tests. These two principles—the first being the structure, the 
second the fold, of the membrane—I am careful to recall, as I 
think there is considerable misapprehension regarding them. 
The chief locality of these fossils was in the south and west of 
England. 
In his chapter on the Continuity of the Chalk, Prof. Thomson 
brings forward several families of ancient fauna as palzolontolo- 
gical evidence in support of his argument. Among these he 
devotes some attention to the Ventriculidz (he calls them Ven- 
triculites, but why? In the same sentence he uses the family 
name Hexactinellide) ; but, though he acknowledges my father’s 
work, and refers to his ‘‘minute and most accurate description 
of their structure,” it does not appear by what follows that he 
has quite comprehended it: ‘‘He (Mr, Toulmin Smith) found 
them to consist of tubes of extreme tenuity, delicately meshed, 
and having between them interspaces usually with very regular 
cubial or octohedral forms” [‘‘ Depths,” &c., p. 482]. This de- 
scription (the Professor will forgive me for saying so) does not 
convey a very clear idea of any structure, and certainly does not 
apply to the Ventriculide : if the word ‘‘tube” here means the 
body of the creature, it may in one sense be partially true of a 9 
few species in each of the genera—Ventriculites, Cephalites, and 
Brachiolites ; but if it is intended to apply to the substance o 
the structure, I must say that it denotes a complete error. M: 
father’s words are, that ‘‘ the membrane of the Ventriculide is 
composed of very delicate fibres,” ‘‘ the fibre is single and solid, 
never fistular,” and that in this structure ‘‘ there are no tubes what- 
ever” (pp. 21,25, 30). My father carefully describes this membrane, 
and marks it as the essential characteristic of the whole family o 
Ventriculidz, Among the thirty-five species, for the most pa 
marked by strong differences, he points out that Ventriculii 
simplex is the type of the whole family, consisting of a single 
membrane without a trace of fold. 
Now, Prof. Thomson gives a figure of the octohedral structure - 
to which I will not take exception, but he writes underneath it, 
“© Vintriculites simplex, Toulmin Smith. Section of the outer 
wall, showing the structure of the silicious net-work.” This 
implies, while citing my father’s name (1) that this structure is 
proper to that species ; and (2) that there is an inner wall. I 
also speaks of the net-work as silicious, while, two pages before, 
it is said, that ‘‘ Mr. Toulmin Smith supposed that the skeleton 
of the Ventriculite had been originally calcareous.” But though 
mistakes of this sort might easily arise through misapprehension, 
I must say I was very much astonished to see the figures, one of 
the entire fossil, the other of the ‘‘outer surface,” given as 
“ Ventriculites simplex, Toulmin Smith,” from Mr. Sanderson’s 
collection (*‘ Depths,” &c., pp. 483, 484.) A glance at Fig.1, 
on the second plate in my father’s book, will show that the name 
