i 
OC Pas ere ae 
Feb. 3, 1870] 
NATURE 
361 
It is hardly possible to exaggerate the importance of the ques- 
tion now under discussion in NATURE, ‘* What was Kant’s view 
of Space?” A mistake there is simply fatal. I therefore rejoice 
to find the columns of that paper are so generously thrown 
open to those who, like myself, are not primarily concerned 
with physical science. But this question, like all others in phi- 
losophy, has a proclivity to indefinite expansion, and unless its 
discussion be rigidly restricted to the main issue involved in it, 
the conductors of NATURE will have to ostracise it. Their 
space is not an infinite form, but a quantum to be carefully 
economised. It is, for example, an unwarrantable waste of that 
commodity to make Hegel the exponent of Kant on a point 
where Hegel taught that Kant was wrong. 
It is fortunate for our interests, as students of Kant, that Mr. 
Lewes, while committing the strange oversight of criticising 
Kant’s Intuition from Hegel’s standpoint, in his last letter 
(NATURE, Jan. 27) enables us to déméler the main issue from 
the mass of questions which entangle it. He evidently, if 
tacitly, slights the plank I threw to him, viz., that Thought, in 
its ultimate relation to Intuition, borrows, or has reflected on it, 
the forms peculiar to Sense. What are Kant’s Begriff vone. 
Raume, Begriff der Zeit, but this? (With these expressions, 
compare the following :—A\lso ist die urspriingliche Vorstellung 
yom Raume Anschauung @ /rioré und nicht Begriff. Transac. 
ésth. s. 3, 4.) This reflection of form is not what Mr. Lewes 
is after. He maintains that, according to Kant, “‘ the activity 
of mind is threefold—Intuitive Thought, Conceptive or Discur- 
sive Thought, and Regulative Thought.” (Is not Regulative 
Thought discursive?) So, then, the main issue between Mr. 
Lewes and (I think) Professor Croom Robertson on the one 
hand, and Professors Sylvester and Huxley, Mr. W. H. S. 
Monck, and myself on the other, is plainly this. Did Kant mean 
to teach that man has Intuitive Thought, t.e., Intellectual Intut- 
tion 2 Now ¢hat I must be understood emphatically to deny ; 
and in the event of the shortcomings of better men than myself, 
I hold myself prepared to establish the negative of that question, 
understanding by Thought the gevws of which Understanding 
and Reason are sfecies, 
Ilford, Jan, 31 C, M. INGLEBY 
Dust and Disease 
THE extremely important discoveries brought to light by Pro- 
fessor Tyndall will call forth great exertions on the part of 
thinking persons to carry his plans into operation, and I have no 
doubt, when due precautions are taken to sift infected air as it 
passes into the lungs of those whose duties take them where con- 
tagion abounds, we shall have the happiest results. 
So great will be the tide of interest in this direction, that I am 
anxious to cast into it a theory I have long held, in hopes that it 
may drift in some one’s way to be turned to use ; I commend it 
to the travelling portion of your readers especially. 
Whilst travelling in some very unhealthy parts of Africa, more 
particularly amongst the marshes bordering on the Shiré and 
Zambesi rivers, it was often necessary to camp at night just 
where the canoe happened to be moored when daylight failed us. 
Reeds, rushes, and mud were never many feet off, and the accu- 
mulation of scum, decaying vegetation, &c., lodged in the sedge, 
made the situation as delightful to mosquitoes as it was trying to 
the constitution of the European. 
Still, with all this, as long as it was possible to rig up a mos- 
quito curtain, I am convinced that really less danger existed in 
thus sleeping in the midst of miasma than in other places where 
less of it was supposed to be present, but where the traveller felt 
no necessity to stretch this thin covering over him. 
I have in this way done canoe journeys of twenty to twenty-five 
days in length without a day’s illness from fever, and I could 
instance similar experiences on the part of others. 
Now the reason I assign is this: the mosquito curtain is to 
miasma, what the Professor’s cotton-wool respirator is to the 
poison of scarlatina, we will say. 
The curtain, after being used once or twice, saturated with 
dew, folded up whilst damp and crammed into the limited 
space generally provided for it in the safest place, becomes 
just so much affected by this treatment that each thread loses its 
smooth glaze, and is soon fluffy and fuzzy for want of a better 
expression. 
The little honeycomb holes in the fine ‘‘ net” are now a series 
of small six-sided sieves, each covered over with the fine filaments 
of cotton which have got disturbed and frayed up. Dew, falling 
upon a surface of this kind, quickly turns it into an exquisitely | 
fine strainer—in fact almost a film of water—through which all 
the air has to pass which is breathed by the person reposing 
beneath it. 
Now, it is an old notion that the miasma which produces the 
bilious remittent fever (the pest of this part of Africa in question) 
and various other diseases of the tropics, cannot pass across 
water. 
I believe that acting upon this theory, the Admiralty provides 
that boats’ crews shall sleep in their boats anchored off shore in 
malarious rivers. However, be this as it may, I have a strong 
belief that the ‘‘ wet sieve” doves stop the poison in some way or 
other, and that it is a great safeguard to the voyager in these 
laces. 
The whole subject of miasm is in the dark ; it is lawless as a 
cause of disease ; it baffles the most astute, but the day may be 
coming when such hints as these of Prof. Tyndall’s shall fit into 
an organised attack upon it, and we shall be able to overcome 
it in a measure. 
A curtain, properly made, and taken care of with that instinct 
which alone is begotten by the buzz of mosquitoes, is perhaps 
the most valuable possession a man can have a gainst deadly 
attacks in the night whilst men are asleep: were its merits 
studied more, we should not find men stuffing their companions 
so perpetually with quinine, to the keeping up an unhealthy tone 
by this abuse alone, and to the confusion of this most invaluable 
medicine when it is really called in to do its duty upon the fever- 
stricken patient. 
Chatham, Jan, 24 Horace WALLER, F.R.G.S. 
Scenery of England and Wales 
THE willingness you have hitherto shown to give authors an 
opportunity of defending themselves against being misunderstood, 
induces me to hope that you will allow me to disclaim being the 
author of certain statements, and to deny the truth of other 
statements, on which an anonymous reviewer in your last number 
mainly founds the charge of boldness he brings against me for 
writing the work entitled ‘‘ Scenery of England and Wales,” &c. 
In one part of the review / amz made to say that I ‘* purposely 
refrained from reading;” in another it is assumed that my reading 
has ‘‘ consisted mainly of the recent journals and magazines ;” 
and further on it is asserted that I wrote the book “ without 
reading.” 
The facts are, that for many years I devoted more or less 
time to reading on the subject of Denudation, and that, as 
stated in the Preface, until lately I purposely refrained from 
‘reading very much (a distinct thing from not reading) lest a 
bias should be given to my opinions.” 
My reason for not quoting the remarks of the late Principal 
Forbes on the glaciers of Norway, was not, as implied by your 
reviewer, because I underrated the denuding power of glaciers, 
but because Forbes said very little on the subject. 
Mrs. Somerville’s estimate of the velocity of the Rhone may 
be incorrect, and perhaps, likewise, her statement that the 
declivity of the river is 1 foot in 2,620; but this is no reason why 
your reviewer should leave the reader to suppose that I misquoted 
Mrs, Somerville. In other parts of the work I have referred to 
the velocities of many currents besides the one off the southern 
promontory of Shetland. 
The argument against denudation by currents, derived from 
the non-displacement of éarnacles, would, I think, never be 
brought forward by any one acquainted with the fact that sea- 
waves often remove stones and large blocks while barnacles in 
the immediate neighbourhood are left undisturbed—that waves 
and currents, by their insinuating, undermining, overturning, and 
removing action, can carry on the work of denudation within a 
few inches of an unabraded rock-surface—and that a certain 
amount of resistance to be overcome is necessary to enable all 
denuding agents to produce effects which can be immediately 
perceived. On the western shore of Morecambe Bay, sea-waves 
and currents detach and remove fragments of limestone rock by 
a lateral process, while the brink of the unremoved mass of 
rock retains its glacial polish; and many other instances illus- 
trative of this subject might be stated. 
The fact that for more than twenty years I have confined my 
observations to England and Wales, and devoted nearly my 
whole time to visiting, revisiting, and studying every part of the 
country, is no reason why I should not have ventured to write a 
work on the Scenery of England and Wales in connection 
with Denudation. The country stands almost alone as regards 
the variety and importance of its geological phenomena, including 
