Fuly 22, 1886] 
NATURE 
205 
Last night (9th inst.) the upper northern sky was obscured 
with cumulous cloud, but in a clear space above the horizon, 
from N. to N.E., a belt of cloud resembling that of the previous 
night extended obliquely. In this case the belt was dark ; but 
beneath, and apparently descending from it, bright luminous 
patches formed of a golden lustre at midnight, and faded out at 
1.30a.m. Wind again from N.W., light. Temperature cool 
for season. 
Examined with a good field-glass, these cloudlets present the 
usual cirrous type in all but singular luminosity, and little (if any) 
of the aurora. - D. J. Rowan 
Dundrum, co. Dublin, July 1o 
Animal Intelligence 
A REMARKABLE instance of animal intelligence has lately 
come under my notice, which I venture to relate as being pos- 
sibly of interest to the readers of NaTuRE. In a neighbour's 
bungalow in this district two of our common house-swallows 
(Airundo javanica) built their nest, selecting as their site for the 
purpose the top of a hanging lamp that hangs in the dining- 
room. As the lamp is either raised or depressed by chains 
fixed to a central counter-weight, these chains pass over pulleys 
fixed to a metal disk above, on which the nest was placed. 
The swallows evidently saw that, if the pulleys were covered 
with mud, moving the lamp either up or down would de- 
stroy the nest; so to avoid this natural result they built over 
each pulley a little dome, allowing sufficient space, both for 
wheel and chain to pass in the hollow so constructed, without 
danger tothe nest, which was not only fully constructed, but the 
young birds were reared without further danger. This is, in 
my opinion, a wonderful example of adaptation to environment, 
and showing a step far beyond what may be contended as instinct 
only. 
I may here add another curious case which seems to point to 
another branch of reasoning. During the dry weather I have 
been constantly annoyed by wasps building up with mud key- 
holes, sometimes keys, blank cartridge cases, and even in one 
case a fen-holder. As I did not care to have my gun charged 
with young wasps, I used to empty out any cartridge case which 
I found closed up with mud, but one cartridge-case in particular 
I noticed had been selected. This one I had left on my office 
table, and each time the wasp closed it un I drew the charge 
of mud and ‘‘grubs,” &c. ; but as frequently the wasp closed it 
up again. I may here mention that the wasp used to deposit 
the egg, and several small grubs in a cell, close over the top, and 
repeat the operation again till the cartridge was full, when the 
mouth would be pasted over with a lid of mud. As I repeat- 
edly knocked out the grub and mud, it appears the wasp started 
a fresh plan. I noticed somewhat to my surprise that the 
mouth of a cartridge I had but a few hours before emptied was 
pasted over, so I thought it would be interesting to see how 
many grubs the wasp had secured in so short atime. I there- 
fore removed the fresh lid, that was still damp, and discovered 
nothing inside! Iam unable to say if this was done to direct 
my attention to one particular cartridge case or not, while another 
spot was being used, but I am inclined to believe such to have 
been the case, for later I noticed a gap made between two 
bundles of letters in one of my pigeon-holes, well built up with 
mud, and, of course, as well packed with grubs. 
Ballangoda, Ceylon, June 14 FREDERICK LEWIS 
Deafness and Signs 
In my studies with regard to the sign-languages I have, like 
others, turned some attention to cases of deafness. In such 
cases the use of signs, not the finger alphabet, but natural or 
conventional signs, such as are used by Indians or by deaf-mutes 
of themselves, have appeared to me to give particular satisfac- 
tion to the sufferer. The nervousness attendant upon attempt- 
ing to make out what is said being avoided, the relief is very 
great, and more attention is given to what is spoken. Of course 
such aid to those untrained is but partial, and English people 
accustomed solely to the use of speech are rather unapt, but 
nevertheless signs are valuable auxiliaries, and will be found 
worth trying. Individuals vary in their capability, but inasmuch 
as many children pass through a period of sign-language, there 
will be many cases of adaptability. Whoever has watched deaf- 
mutes conversing, without the finger alphabet or without lip- 
reading, will recognise the satisfaction they receive from their | 
intercourse by signs. My only object is to call attention to 
what has been found by experience to be an acceptable help, 
and which may be extended in its application. 
HYDE CLARKE 
The Duration of Germ-Life in Water 
A RECENT announcement by Messrs. Crookes, Odling, and 
Tidy, that Bacillus anthracis in water approximately devoid of 
nutrient material after ‘‘a few hours” loses its power to multiply 
in suitable culture-media, induces me to send you a note of my 
own results in the same domain. 
My observations were commenced in 1877, but were shortly 
os suspended and not resumed in earnest until May 
1885. 
So far I have worked only with the various forms of organ- 
isms which chanced to be present in the water—usually distilled 
—employed. Fora preliminary investigation I regard this as 
preferable to operating on pure cultures ; one is more likely to 
be concerned with organisms of aqueous habitat naturally, and 
one sees which kinds predominate from time to time, and which 
survive. 
In dealing with an indefinite variety of micro organisms it is 
necessary, of course, to be extremely rigid in one’s precautions to 
guard against intrusion of foreign germs, an intrusion which 
cannot be detected as in the case of pure cultures. On this 
account I abandoned my original sodas oferandi—it was almost 
identical with that of Mr. Crookes and his colleagues—and 
adopted the arrangement of tubes described and figured in a 
paper by Mr. Blunt and myself in Proc. Roy. Soc., vol. xxviii. 
p. 202. 
Of a series of such tubes containing distilled water, originally 
rich in germ-life, kept at a temperature varying from 18° C. to 
21° C., and examined at intervals from May 2, 1885, down to 
now, I find that in every one micro-organisms have sooner or 
later developed on the addition of the nutrient material. 
Each tube is a microcosm, and it has been most interesting to 
observe how, as elsewhere, as time went on, the first dominant 
form has grown more and more feeble, until it seems to have 
become extinct, and is now succeeded by races of quite different 
kind. Whether the new order will yet give place to others re- 
mains to be seen, I can at any rate say confidently that _micro- 
organisms vary greatly in the duration of their life in distilled 
water, and that some forms may survive for at least fourteen 
months in that medium at an ordinary temperature. 
Chelmsford, July 19 ARTHUR DOWNES 
The Bagshot Beds 
In reply to the letter from Mr. Irving in NaTuRE of July 8 
(p. 217), I beg to state that a mere abstract of the paper on the 
Bagshot Beds by Mr. Herries and myself was read at the meet- 
ing of the Geological Society on June 9, on which occasion Mr. 
Irving was not present; that the report of our remarks in 
Nature of July t (p. 210) only purports to give the conclu- 
sions at which we arrive, and not the evidence by which they 
are supported. We trust therefore that your readers will reserve 
their judgment until the entire paper is published. 
Horace W. MONCKTON 
1, Hare Court, Temple, July 17 
A Lubricant for Brass Work 
Many besides myself have probably been inconvenienced by 
the corrosive action of ordinary lubricants—lard, grease, &c,— 
upon brass and copper, which causes the plugs of stop-cocks to 
leak or get fixed in their places, and does much damage to air- 
pump plates. 
Melted india-rubber answers fairly, but it has too little 
“‘body,” and too much glutinosity ; moreover, it does, un- 
doubtedly, in course of time, harden into a brittle, resinous 
substance. Vaseline is quite without action on brass, and never 
hardens ; but it has not sufficient tenacity and adhesiveness. 
A mixture of two parts by weight of vaseline (the common 
thick brown kind) and one part of melted india-rubber seems to 
combine the good qualities of both without the drawbacks of 
either. 
The india-rubber should, of course, be pure (not vulcanised), 
and should be cut up into shreds and melted at the lowest 
possible temperature in an iron cup, being constantly pressed 
