Iron: An Illustrated Weekly Journal for Iron and Steel Manufacturers ...

a sort of acidification." To what is this acidification of the leaf in the autumnal season owing, but to the diminished action of the solar rays, in consequence of which a portion of the carbonic acid remaining undécomposed within them produces this change in their colour; but from the above simple experiment, it appears to be drawn up and diffused over their sur face through the stem, together with the water, and thus it seems to occasion also the drop of the leaves, while it is probably instrumental in preserving some degree of vitality in the plants, instead of suffering them absolutely to wither and perish during the winter season. So far as any inferences can be deduced from these minute, single experiments, it would appear that carbonic acid is conveyed to the leaves, both through the stems from the sap, and from the moisture of the atmosphere, the larger portion coming from the latter source when opportunities are afforded by the presence of moisture thus impregnated in it, or, perhaps, also by dry carbonic acid floating in the air; but such inquiries require to be more extensively pursued before we can arrive at certain and correct conclusions.

376

abounded; and Dr. Priestley gives the
following interesting account of several
experiments with the willow plant growe
ing in "inflammable air" obtained from
a marsh-probably carburetted hydro-
gen: "I put the stalk of a willow plant
into an inverted jar full of water, while E
the top of it was in a jar of inflammables
air. In these circumstances a sinall
quantity of air was collected in the in-
verted jar, and it was evidently better
than common air." In another experi-
ment three-fourths of an ounce measures
of very pure oxygen was collected under
the same circumstances. "A sign of
the great vigour of the plants growing in
inflammable air was the vivid greenness
not only of the leaves that were in
the air, but of those also that were y
under water, and the length of time that
they continued in those circumstances;
whereas, in general, when the plant was
in common air, the leaves that were
under water soon became discoloured and
perished. These leaves, on the contrary,
not only continued green, but were
always loaded with air-bubbles." In
some experiments on water impregnated.
with carbonic acid, the doctor observed
an abundant growth of green vegetation,
while water unimpregnated with this.
gas yielded no such result. From these
facts and experiments compared together:
it appears evident that carbon and hy
drogen combine in producing the sub-
stance and the verdure of the leaves. In
the ordinary course of nature the hydro-
gen is probably obtained by a decomposi
tion of water; but in those cases in which
it is presented to the plants in a state of
separation from oxygen, the union of
carbon and hydrogen appears to proceed
with extraordinary facility. As the case
related by M. Humboldt is perhaps the
only instance in which green leaves have
been observed growing in darkness, we
have reason to conclude that light is the
ordinary instrument by which hydrogen,
as well as carbon, is separated from its
oxygen; but as in that case there appears
to have been no instrument, excepting
the caloric of the hydrogen to supply its
place, are we not necessarily led to the
inference that they are, in this respect at
least, identical? It seems highly pro
bable that carbonic acid coming in con
tact with hydrogen gas in this mine, their
tendency to union in the substance of the

As much hydrogen enters into the substance of plants, aud, from various experiments, it appears to unite with carbon in producing the green colour of the leaf, it must either be obtained internally from the sap, or from the atmosphere, by an action of the leaves. This is in general probably accompanied with the decomposition of water, to which process it is likely that there is a similar necessity for the agency of light, as in the case of carbonic acid. We are not aware that in the ordinary course of nature hydrogen, in a state of separation from oxygen in the form of water, is ever presented to the leaves. But when they are by artificial means, or by some extraordinary concurrence of circumstances, exposed to such an atmosphere, the effects are remarkable. I have repeatedly observed that sprigs of spearment not only live équally well in it as in common air, but that their verdure is heightened; and for one or two days after being introduced to it, their ordinary transpiration of moisture has been almost wholly suspended! M, Humboldt informs us, that he met with green plants growing in complete darker ness at the bottom of one of the mines of Friesburg, in which hydrogen gasoideaves became stronger than their affinity #koy obuu guíesú to botan

142

NEW MODE OP HEATING ROOKBINDERS LETTERING-TOOLS.

to caloric in the gaseous state, which thus becoming disengaged, performed the function of light in promoting their union, and also in carrying forward the aqueous transpiration of the plants. Priestley's willow plants appear to have been under similar but more advantageous circumstances from the presence of carburetted-hydrogen; as in this case, light and caloric probably co-operated in forwarding the action of the plants upon the two elements of carbon and hydrogen, and producing the disengagement of the oxygen. What is the general inference to be deduced from the above premises? Is it not that the soil administers the due supplies of moisture in conjunction with such other materials as it holds in solution to the roots of plants, which, by the action of the solar fluid, chiefly under the form of light, are essential to their vitality and growth? And is not this effect, together with the decomposition of both carbonic acid and water by the action of the same fluid on their upper extremities, so much concurring evidence in favour of the electro-chemical agency of the same pure imponderable fluid in carrying forward the several processes of vegetation ?

I remain, Sir,

Yours respectfully,

Maidstone, May 23, 1936.

T. PINE.

P. S. In a letter received from Mr. Weekes on the 15th inst., he fully confirms my statement of "the necessary presence of carbonic acid in atmospheric air in order to the production of oxygen from the leaves of plants." He makes mention of some experiments which he has made on the presence of carbonic acid at different elevations in the atmosphere, which, I trust, he will communicate to the public on some future occasion, as they cannot but be highly interesting.

NEW MODE OF HEATING BOOKBINDERS'
LETTERING-TOOLS.

Sir, It is a well-known fact, that heat diffuses itself through metallic bodies with great rapidity; and this is exemplified when we plunge a piece of brass into melted lead, the former metal almost instantly attaining a degree of temperature equal to that of the latter.

This circumstance has induced me to

conclude, that bookbinders' tools might be heated much more speedily, and with better effect, by dipping them into fused lead, or printers' type metal, or an alloy of lead and tin, than by exposing them, in the usual way, to a coke or charcoal fire. Sand floating on the surface of the fluid metal would, in a great degree, ptevent the escape of its fumes, and also retard its combination with the oxygen of the atmosphere,

An experienced bookbinder, I stated my views, expressed his that the adoption of the plan would be found very advantageous in finishing. shops, where gilding forms so important a part of the business. I remain, Sir, Yours respectfully,

Derby.

T. COGGAN.

EFFECT OF THE VELOCITY OF AIR UPON
ITS USE IN SMELTING IRON.

M. Teploff, one of the Russian Mining Corps, in an article on the improvements recently introduced into the smelting of iron in Russia, makes the following statement. In the smelting furnaces of the Ural, where the quantity and velocity of the blast are properly regulated, 14 of pig iron is obtained by 1 of charcoal fuel, while in other furnaces they obtain but 4 and 6 by the same comsumption of fuel.

The velocity of the blast being increased, the heat within is increased, without a corre sponding consumption of fuel. In an experiment made by order of the government, it was found that one hundred cubic feet of air, under a pressure of two inches of mer cury, produced the same effect as two hundred cubic feet, under a pressure of one e inch, with this difference, that, in the latter case, twice the fuel was consumed, which was required in the former case.

In one furnace which is mentioned, 22,000lbs. of iron were obtained in twentyfour hours, by 16,000 lbs. of charcoal. Previous to the due regulation of the draught, they consumed twice this amount of fuel for the same yield of iron.

This economy is obtained by duly proportioning to each other the size of the blast pipe, and the pressure of the draught. The relation of these to each other, varies with the furnace.

M. Teploff asserts that the results thus obtained exceed those with the hot-air blast, but it does not appear that any comparisons have been made under his examination, and with the charcoal fuel.

To regulate the draught, it is recom

mended to place two mercury or water-gauges, one near the blast-pipe, the other near the governor of the blowing-machine. By varying the pressure, and the diameter of the nozzle of the blast-pipe, making the latter smaller as the former is increased, and vice versa, the best proportion is to be ascertained, Annales des Mines, vol. vii.

EDWARD TROUGHTON, ESQ., F.R.S., L. AND E., F.R.A.S. AND F.R.S.C.E.

The late Edward Troughton was born in a small village in Cumberland, in the year 1754, where he received merely a common education in the village-school. When seventeen years of age he came to London, and apprenticed himself to his brother John, a respectable mathematical instrument-maker, carrying on business at No. 136, Fleet-street; and when out of his time was taken into partnership, and ultimately succeeded to the business, and ever after continued to reside there; and it is not a little remarkable, that the same spot has been successively occupied by mathematical instrument-makers of cele brity for nearly 200 years; and here a Sutton, a Wright, a Cole, and a Troughton, laboured with unwearied zeal for the advancement of science. In a very short time after Mr. Troughton's arrival in the metropolis, he began to display that great originality of genius, which in the end made all scientific men look up to him for the means of prosecuting their pursuits with the fullest effectfor be it remembered, that the sublime study of astronomy must ever be obscure without instruments of the most accurate execution, because the theorems of mathematicians are' useless without data to act on-and with this he supplied them; presenting to all compe-tent persons the means of dividing instruments with the most perfect accuracy, and by which they have been graduated to such a degree of exactness, that error is not to be discovered in them even by high optical powers; and many of his instruments of large dimensions are placed in various ob servatories, and by them a catalogue of the fixed stars, and the sun, moon, and planets, are now ascertained, and published in the Nautical Almanac. Many other skilful artists have also acted upon his improvement. The stability, accuracy, and commodious arrangement of his instruments leave nothing for the astronomer but to use them with care, as it is a fact, that the declination of some of the fixed stars have been ascertained by them to one-third of a second. It is unnecessary to follow Mr. Troughton step by step, but a reference to a few of his great undertakings cannot be without interest. Royal Observatory is furnished with a mural circle, a transit instrument, and a zenith

The

sector, all of his contrivance; and the last was completed by him when in his 79th year: also, an equatorial instrument, for Trinity College, Dublin; and which is now stationed at Armagh and a meridian circle (made for Stephen Groombridge, Esq.), now belonging to Sir James South; the whole of which are specimens not perhaps to be equalled either in beauty or figure, or perfect accuracy. He also remodelled the continental instruments so as to make the repeating circle of the Chevalier Borda, and the reflecting circle of Mayer, almost original inventions of his own. His nautical instruments, also, both as to construction and accuracy, are beyond all praise; and by them the mariner is now indeed enabled to mark a road on the trackless ocean." Nor were his great labours wholly unrewarded; for the Royal Society, in 1809, presented him with the Copley' Medal, for his elegant and valuable paper on Dividing. On the 7th of April, 1823, he received the freedom of the Clock Makers' Company; and in January, 1830, the King of Denmark presented him with a valuable gold medal, as an acknowledgment of his great and important improvements. In his latter years he devoted himself entirely to severe study and scientific pursuit; and laboured not merely in abstract theory, but for the improvement and direct benefit of the civilised world. Retaining his faculties to the last, he died on the 12th of June, 1835; and, according to his request, his remains were deposited in the General Cemetery, Kensall Green; and were followed by many, and deeply regretted by all the scientific' world.-New Monthly Magazine.

NOTES AND NOTICES,

New Power.-We learn from Frankfort that there has been communicated to the Society of Natural Sciences of that city a discovery of a new motive power, created by means of a galvanic hattery, the action of which will supersede the use of steam, be more powerful, much less expensive, and less dangerous.-Morning Herald.

National School of Design.- In the course of a discussion which arose in the House of Commons on Monday last upon the vote of 25 8601, for new buildings at the British Museum, the Chancellor of the Exchequer (Mr. Spring Rice) said, that be intended to lay before the House a supplementary estimate for the purpose of establishing a school of design, with a view generally to the cultivation of the popular taste, and to the practical improvement of our manufactures. He trusted that the proposed institution would be well suited to serve as a model according to which other schools might be formed in provincial places.

The Thames Tunnel.-This stupendous undertaking is proceeding s owly, but steadily towards completion; nor has any obstruction occurred since the works were re-opened. The men work night and day; there are three sets of men employed, which relieve each other every eight hours. Each set consists of 112 men, and there are numerous supernumeraries, ready to supply any casual vacancy. During the eight hours of work they are

Holborn, so as to affect a direct junction with Og ford-street; and, executing divers other plans of unques fonable ntility. And all this, and more, the Alderman calculated (it is not known by what elaborate process) might be done at an outlay of only 800,000. By a turn of Fortune's wheel, the projector of these mighty alterations has this sum at his own disposal; and how could he more glorious. ly display his civic patriotism than by carrying into effect his magnificent ideas for changing the whole aspect of the metropolis over which he twice presided as Lord Mayor? It is to be feared, how ever, maugre his own estimate, that he would arrive at the bottom of his purse, some time before he had got to the end of his trifling undertaking.-F. H.

French Theory and English Practice-It is not a little singular, that, while England is making so great a progress in the actual establish ent of railways, the French have published a much larger number of works on their mathematical theory; although this is, perhaps, not by any means the first instance in which the same state of things has occurred. A Colonel de Pambour has just added to the rather long list of publications by his coun trymen on the subject, a very elaborate book of calculations on railway theorems, in which he lays down his positions rather more dogmatically than his little experience (all apparently gained in Eng land) seems to warrant. He has not, however, much to fear from his English competitors in the line, the principal of whom are Mr. Macneil, of "canal navigation" celebrity, and John Herapath, Esq.-F. H.

Truth stronger than Fiction.-It is a well-ascer tained, but rather unaccountable fart, that, notwithstanding the amazing increase of late years in the manufacture of steel pens, there has not been the slightest falling off in the extent of the quill trade.-F. H.

Communications received from Mr. Tracey Mr. Dickson Mr. Barton A Country Teacher.