Dec. 7, 1882 | 
NATURE 
127 
and a portion of the anterior “segments dirty ‘yellowish white. 
I do rot yet know the perfect insect. ‘The larva feeds on the 
wild balsam. The general colour of this larva at once reminded 
me of two abnormally coloured larvz of the common death’s- 
head moth that I had brought to me from a potato field in Jersey 
some years ago, together with otkers of the ordinary colour, 
One was full grown and another half grown, The general 
colour of these was brown with fine black markings and without 
a trace of green. The anterior segments were a pale dirty 
cream colour. There were no ocelli or diagonal stripes on the 
sides. 
I have not seen recorded any similar case of abnormal colsuring 
in the larva of the death’s-head moth, but the fact is intere-ting 
as indicating a common ancestry in two moths which are pro- 
bably now classed in different genera. 
E. R. JOHNSON 
Surgeon Major, Bengal Medical Department 
Shillong, October 16 
[The form of death’s-head larva alluded to is not uncommon ; 
it is a dimorphic condition and finds its parallel in many larvee 
of Sphingide. Ep.] 
The Fertilisation of the Common Speedwell 
ALTHOUGH it is the wrong time of the year for observing 
flowers, it will perhaps not seem out of place to draw the atten- 
tion of your readers to the fertilisation of the common Speedwell 
( Veronica officinalis), ‘he flowers in the plant hang downwards, 
so as to bring the nearly flat corolla a little under the perpendi- 
cular. The two stamens project outwards and downwards on 
each side of the pistil, which also hangs down, but not so much 
as the stamens. ‘These latter are very much narrowed at the 
base. The flower is in this species, proterandrous, and the 
corolla, as soon as the stamens have shed their pollen, becomes 
slightly loose. 
It at first sight seems quite impossible for either cross or self- 
fertilisation to take place, as the stamens are quite away from 
the pistil, and, owing to the position of the flower, insects are 
compelled to alight in front. 
One morning last summer, however, in considering the struc- 
ture of the flower, &c., I was led to conclude that the explana- 
tion must lie in the insect’s mode of settling up nit, and accord- 
ingly watched two or three plants. In about half an hour’s 
time I had the pleasure of seeing a large fly in the act of ferti- 
lisation. As the corolla was flat, and the flower hung down, 
there was no foothold there, so the insect clasped each of the 
stamens with its forefeet. Being thin at the base, they were 
drawn together, and the anthers meeting just below the pistil, 
dusted the front of its head with the pollen. 
On comparing a large number of flowers, I found that when 
just open, the pistil stocd up above the point at which the two 
anthers would meet, but that in older flowers, especially after 
the anthers had shed their pollen, it was inclined downwards, 
If this observation is verified, it will show a most striking adap- 
tation for preventing celf-fertilisation. 
I may add that in one of the smaller flowered species, V. 
hede efolia, the stamens and pistil are quite close to each other, 
so that self-fertili ation must here be the rule. ‘The corolla is 
also not so easily detached. A, MACKENZIE STAPLEY 
The Owens College, Manchester, November 20 
Wartmann’s Rheolyzer 
You gave in NATURE a report on ‘‘ Wartmann’s Kheolyzer.” 
I beg to say that I invented and constructed the same appa- 
ratus long ago, and described it in the ‘‘Sitzungsberichte d. 
Wiener ka:t Akademie d. Wissenschaften,” July, 1877, under 
the name of ‘‘Rheonom.” Some months after that a tair report 
of my paper appeared in ‘‘ Beiblatter zu Wiedemann’s Annalen.” 
My instrument was for some years in the hands of several physi- 
ologi-ts. Prof, Yeo was present when I made experiments 
with it in Prof. I udwig’s laboratory in Leipzig in the year 1878, 
and Prof. I, du Bois-Reymond has it also in his collection of 
physiological and physical instruments fer more than five years. 
There is no doubt that Prof, Wartmenn was not acquainted with 
my apparatus when he described his, but I cannt be expec’ed 
to see my invention ascribed to another and keep silent. So 
you will oblige me very much in correcting the above-mentioned 
mistake in your paper. ERNST VON FLEISCHE 
Vienna, Wahringerstrasse 11, November 30 
Pollution of the Atmosphere 
THERE was a letter in NATURE some time since, calling 
attention to the pollution of the atmosphere by the burning of 
coal ; and it was calculated that in the year 1900, all animal life 
would cease, from the amount of carbonic dioxide; but the 
author had overlooked the fact that the rain is continually 
cleansing the atmosphere of this, and the fall of this rain on the 
grcund, and the combination of this with various salts ; besides, 
the oceans alone would absorb their own Fulk at normal pres- 
sure, but at an increased pressure of, say half a mile deep, 
vould dis:olve more than we are likely to need for hundreds of 
years. 
But there are other products of combustion, or rather of in- 
complete combustion, that are not brought down in this manner 
by rain, as hydrogen and the hydrcecarhons, chiefly marsh-gas 
and ethylene. The latter has, I believe, been observed by the 
spectroscope on the Alps, and was supposed to have come from 
space, 
Since the year 1854 (as near as I can estimate) there has been 
buri.t 10,000 million tons of coal ; and if we say (in its con- 
sum tion by household grates, leakage by gas-pipes, &c.) 1-100th 
escapes, then 100 million tons of hydrogen and hydrocarbons 
are floating in the atmosphere, or 1-10,000,00oth part in bulk ; 
if we say the average proportion of hydrogen to be ‘45, end of 
marsh gas *35, and of ethylene ‘4, we have °84 per cent. of 
gases that are lighter than air, and it is more than probable that 
the law of diffusion of gases, asdemonstrated with jars, does not 
apply to the atmosphere. The cases are not parallel: in the air 
we have unconfined space, pre‘sure, and temperature diminishing 
infinitely, conditions favourable to the lighter and the gas with 
the greater amount of specific heat rising and maintaining its 
elevation, especially as we know that in /avge halls carbonic 
dioxide is found in larger quantities on the floor. According to 
Prof. Tyndall’s researches, hydrogen, marsh gas, and ethylene 
have the property in a very high degree of absorbing and radiat- 
ing heat, and so much so that a very small proportion, of only 
say ore thousandth part, had very great effect. From this we 
may conclude that the increasing pollution of the atmosphere 
will have a marked influence on the climate of the world. The 
mountainous regions will be colder, the Arctic regions will be 
colder, the tropics will be warmer, and throughout the world 
the nights will be colder, and the days warmer. In the Tem- 
perate Zone winter will be colder, and generally differences will 
be greater, winds, storms, rainfall greater. H, A. PHILLIPS 
Tanton Houre, Stokesley, November 23 
A Modern Rip Van Winkle 
WHEN Mr, Evans asks whether it is impossible for ‘‘the so- 
called flint implements and flint flakes to have been formed by 
natiral causes’” he surely must have had a scientific nap of furty 
or fifty years. He can answer his question by going to any good 
museum and inspecting the beautifully and clearly manufactured 
implements which the Curator will show him. 
November 28 
SALTBURN 
GOOLDEN’S SIMPLE DIP-CIRCLE 
DIPPING-NEEDLE suitable for the requirements 
« of schools and science classes has long been a 
desideratum, there having been no instrument obtainable 
hitherto which would at a moderate cost afford results of 
sufficient accuracy. Between the mere needle sus- 
pended in a simple stirrup of brass, and the delicate 
and complicated dip circles of standard pattern there 
has been no intermediate form of instrument. This de- 
ficiency, has, however, been remedied by Mr. Walter 
Goolden, M.A., Science Master in Tonbridge School, 
who, in conjunction with Mr. C. Casella, has designed the 
form of portable dip-circle depicted in the figure, which 
possesses several novel points. The needle, which is 33 
inches in length, is poised upon an accurate axis working 
in sapphire centres, and magnetised once for all. In 
order to ensure the coincidence of the centre of gravity 
with the centre of suspension, two very light adjustible 
counterpoises are fixed to the needle, one of them being 
capable of being moved parallel to the length of the 
needle, the other lying at right angles to the first, and 
