134 

stem ; in the second we have leaves and their modifications ; in 
the third, inflorescence and the whorls of the flower, while the 
fourth presents us with the pistil, oyule, and seed, and the organs 
of flowerless plants. 
ing, diagrams, that is, artificial representations of typical struc- 
ture. They are well and clearly drawn, and sufficiently coloured 
to add to their lifelikeness. With these sheets, and either 
Henslow’s series, or better still, a few hand-made ones on a 
larger scale, and actually taken from life, the botanical lecturer 
would be well provided ; and the comparatively low price at 
which they are published ought to insure for them a very large 
sale. The handbooks which accompany them are admirably 
drawn up. 
From China samples of Poyang Lake coal have been for- 
warded to the Admiralty authorities in the hope that they may 
be found useful for the navy in that station. 
Tue Government of India has taken further measures for 
carrying on coal borings in Central India, but only in Berar, and 
not in the Nizam’s dominions. 
Tue Indian Government have again deputed Mr. T. W. H. 
Iughes, of the Geological Survey Department, to prosecute the 
investigation of the Wurda River ceal-beds in the Central Pro- 
vinces, and to report on the line of railway best calculated to 
develop the collieries. 
Our Darjeeling hill district of India is likely at length to ex- 
perience a development of its mineral produce, instead of being 
left to depend on tea culture. Limestone, copper, and iron have 
been discovered not only in the Darjeeling territory, but also in 
the lately annexed Dooars of Bhootan. The Nepaulese have 
applied to work the iron ore, and the Commissioner of Kooch 
‘Behar has been authorised to divide the tract into sections, and 
to let out the mineral privileges by the year to the highest bidder. 
A VERY important discovery of silver is reported from 
‘Copiapo, in Chile, which has a large silver district. E] Carmen 
Mine is now producing 16,000 mares of silver per month ; that 
is 128,000 ounces, worth about 32,000/. 
Mr. JAMEs GALBRAITH sends to the Avarat and Pleasant 
Creek Advertiser (Victoria), of Sept. 16th, an account of some 
huge boulders found near the townships of Hamilton and Cole- 
yaine, which he believes to have been deposited there by the 
agency of ice. He states that the whole of the western district 
of Victoria is covered with boulder clay. The ironstone gravel 
called buck-shot, which is found in patches on the surface and 
at’a short distance below the surface, all over the plains to the 
south of Ararat and Beaufort, is, no doubt, a deposit from 
floating ice. The ‘grey stone” on the Ararat and Port Fairy 
road has been floated toits present position by ice; anda number 
of granite boulders on the road between Moyston and Ararat, 
some of them a great deal larger than the ‘‘grey stone,” must 
have been brought to their present position by the same agency. 
No polished or striated rocks have, however, as yet been detected 
in the colony. 
WE learn from the Vew York Times that an ice machine, con- 
structed on Tellier’s principle, is now being exhibited in the 
“United States. The material used is gaseous ammonia, which is 
liquefied by pressure. It is said that the machine will make 100 
tons a day, at a cost of four or five shillings per ton; and that 
the ice made by it is transparent and durable. The cooling effect 
of the vaporisation of liquefied ammonia may be applied to 
chambers containing articles of food to be preserved, or refrige- 
rators might be constructed on any scale. The holds of ships 
could thus be converted into refrigerating chambers with the 
greatest ease, offering a ready means for the conveyance of meat 
- from one port to another in a wholesome state. 
Many of the drawings are, strictly speak- | 
NATURE 

| 

BALLOON ASCENTS FOR MILITARY PURPOSES 
II. 
EING detained in England by unavoidable circumstances 
for some time longer than I expected, I will try to give 
the British public an adequate view of the action of our French 
Institute in the matter of balloon navigation ; and will confine 
my criticism to an exposition of M. Dupuy de Lome’s own 
views, which were supported by the Government, so far as to 
give to this learned man a credit of nearly 2,000/. for the con- 
struction of his balloon. Perhaps the observations I have pub- 
lished in the Zzler/é and offered to some of his assistants in 
private conferences, have produced some alteration in the original 
scheme. It isa matter of which I cannot be made aware by 
any means, and I must suppose things to be as they were when 
I left Paris in my own balloon. 
M. Dupuy de Lome’s balloon was to be constructed out of 
silk, and I understood that people were engaged in looking 
after the stuff in different Parisian fancy shops. But it requires 
a great deal of search to find silk enough to construct a large 
balloon somewhat larger than Mr. Coxwell’s ‘“Research ” and ~ 
having a larger surface besides in consequence of its intended 
elongated form, the spherical form being, as is known, the one 
which offers the largest capacity for the smallest surface. 
It may be well to remark that balloons are somewhat elongated 
in the present fashion of building them, the elongation being 
vertical instead of horizontal as required by M. Dupuy de Lome’s 
scheme. But the elongation of the balloon is a thing of which 
we will speak more fully in another place. 
M. Dupuy de Lome was not afraid to have his balloon shaped 
like an egg, or, rather, like a fish with two tails and no head, but 
he did not wish ta try it with pure hydrogen gas. Itis not because 
he thinks that hydrogen gas is too expensive or too difficult to 
prepare, it is only because he supposes that hydrogen gas would 
escape in spite of varnishing. I cannot agree with him in this 
respect, not only because my friend Giffard’s balloons have 
proved perfectly hydrogen-tight, but principally because ordinary 
balloons filled with hydrogen have done good service. Amongst 
these balloons I may mention the one which conducted the™ 
unfortunate Worth to be lodged in a Cologne cell, not by any 
fault of its gas-holding power, but merely because aéronauts were 
foolish enough to open their valve when Prussians were firing at 
them, and preferred trusting to Prussian humanity to relying 
upon the dark mantle of the night. 
Official people engaged in ballooning seem to have strong 
prejudices against hydrogen gas, as may be noticed from their 
acts; the battery I had caused to be constructed for filling 
poor ‘‘Liberté,” having been wholly disregarded by them as unfit 
for use. 
Many inventors have published descriptions of working aérostats, 
but very few of them were really professional aéronauts. I shall be 
justified by facts in stating that scarcely any of them was in a posi- 
tion to form an adequate idea of the most essential features of any 
really scientific scheme. Almost everyone of them has forgotten 
that the principal condition of success is an easy working. M. 
Dupuy de Lome has not avoided that fault, and his balloon is to 
be shaped, as we have remarked, like a fish, which is to be kept 
in an horizontal position. That condition is very difficult to ac- 
complish when you have to look to so many other things at the 
same time. M. Dupuy de Lome is so well aware of the difficulty of 
having his balloon always progressing horizontally, that he pro- 
poses to get rid of it by keeping the balloon always filled either 
with gas, or with ordinary air by means of a pump. It is an 
instance of avoiding our old French saying, Le reméde est pire 
que le mal, ‘his saying is so much the more justified, that M. 
Dupuy de Lome is not contented with sending air into his bal- 
loon when it is required to fill it. He has constructed ready for 
the purpose a special balloon, which is to be enclosed within the 
large one, and which being alternately filled and unfilled accord- 
ing to the requirements of the external pressure, keeps the bal- 
loon always in a state of fullexpansion. The pressure inwards is 
always a little greater than the pressure outwards, which is in itself 
a new objection, as this artificial pressure increases the rate of es- 
cape for the gas by the small holes which are unavoidably so 
numerous in the! whole surface. Besides, if there are some de- 
fective places, they may probably be opened by that pressure. 
As you may understand from this explanation, M. Dupuy de 
Lome was very careful, and his scheme is worked out with every 
required detail, to show the corollaries which follow from the first 
assumptions. M. Dupuy de Lome being a very clever ship con- 
| Dec. 15, 1870 
‘er 
olens 
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