Obrazy na stronie
PDF
ePub

CHEMICAL News,
July 21, 1876.
Notes on Blowpipe Analysis.

27 end of the arm which indicates the force on a dial; and PROCEEDINGS OF SOCIETIES. in another instance by the air acting upon hollow cylin. drical cups hung in the current, by which a finger is worked on a dial plate. He also describes various water- NEWCASTLE UPON-TYNE CHEMICAL SOCIETY. gauges, both for ordinary and for great precision, includ. ing, amongst the latter, one having one of the limbs

General Meeting, March 23rd, 1876. inclined. These are apparently the principal anemometers which

John PATTINSON, President, in the Chair. have as yet been introduced, either above or below ground. It is possible, however, that others may have

DISCUSSION ON Jones AND WALSH'S DECOMPOSING been used, and even that some of them may have been

FURNACE. invented by other persons than those whose names they

(Concluded from p. 268.) now bear. Indeed, looking at the instruments generally, Mr. H. L. PATTINSON said he had visited the works of there is little more of any principle in them beyond Messrs. Jones and Co., and he had seen the first pan, and what appears either in the windmill, or what may be ex. more recently the larger pan, in operation and he could emplified by a light substance hung from a cord.

certainly bear testimony to the fact of there being no gas

escape. Of course he could not say anything as to the (To be continued.)

quantity of the gas condensed. He was very much satisfied with the admirable way in which the material seemed to be wrought. He never saw a more beautiful sulphate in his life. There was not a lump in it larger

than the size of a hazel nut, and even these lumps when NOTES ON BLOWPIPE ANALYSIS.

broken showed a perfect decomposition. He thought that By H. B. CORNWALL.

if Mr. Jones would give them some of the tests of the sulphate they would be interesting. Those which he got

when he was there were very good indeed. If he charged In a note published in the American Chemist, March, 1872, his memory rightly there was something like i per cent I stated that Van Kobell's iodide of potassium and sul of free acid, showing probably that there was not a very phur test for bismuth gave also a marked reaction with high temperature, and there was a very small quantity of lead compounds. The characteristic yellow sublimate chloride-three-tenths per cent-showing that the decom. which it affords with lead compounds is nearly as volatile position was very perfect. He thought it would be well as the real sublimate obtained by it with bismuth com- to supplement some of Mr. Jones's remarks also on that pounds, both of them being formed at a greater distance point; if by any accident an insufficient quantity of acid from the assay than the simple yellow coatings of oxides had been added to the salt, they could correct that by of lead and bismuth which frequently accompany them. / adding a little acid during the process and before the The iodide of potassium and sulphur mixture constitutes charge was withdrawn. It was only necessary to sprinkle a simple and very delicate test for lead, even in presence in the additional estimated quantity of acid. That was of a very large amount of bismuth, as experiments will very rapidly disseminated through the mass, and thus show, and I direct the students to rely chiefly upon it; succeeded in bringing it to a perfect decomposition. On remembering only that the jodide of lead (?) sublimate is the other hand, if there was an excess of acid, it was only much more volatile than the simple yellow coating of necessary to put in a little salt; that also was rapidly oxide of bismuth or lead, which always lies near the mixed by the action of the machine and took up any assay. A few precautions are necessary in using the excess of free acid. He thought that the output, even of mixture as a test for lead, and also for bismuth to a cer. the furnace which Messrs. Jones now had at work, could tain extent.

be very largely increased by a better draught. He thought Mercury compounds will often afford a yellow, some. Messrs. Jones would probably agree with him that the times a reddish sublimate with the mixture ; sulphide of deficient draught was probably owing to their having, arsenic in large quantities, a yellow sublimate ; sulphide from the nature of the place, been obliged to take the flue of antimony, an orange, sometimes a reddish sublimate ; below the floor. It suddenly dropped from the roof of the cadmium compounds the yellowish brown coating of furnace under ground, then rose again after a considerable cadmium oxide, which might mislead beginners; ail of distance, and as they all knew that a pulldown draught these can be removed by a preliminary treatment with a was disadvantageous, they would probably with a better moderate oxidising flame, to such an extent as not to arrangement of the draught get a better result. The first interfere with the lead or bismuth reaction, and they furnace, he thought, was working much more satisfacshould be so removed when present in large quantities. torily, and, for its size, turning out a larger quantity of Finally, some tin compounds yield a yellowish sublimate sulphate. The draught was, at all events, sufficient, even with the iodide mixture, but it is very near the assay, and in the large furnace, to do away with any nuisance such quickly becomes white on continuing the blast. These as we have even in our well-draughted open condensing facts have partly been brought to my notice during prac- furnaces. There was no nuisance when the charge was tice with classes, and therefore will be of interest mainly drawn, and they all as practical manufacturers, knew to beginners, who are most liable to be deceived by the what a nuisance it was having the batches imperfectly reactions given. The mixture is, however, highly to be wrought. There was no gas that he could complain of, recommended in testing for lead, having given indications and he thoug t nobody could. There was a little pungent of that metal in bronze and cadmiferous calamine, when odour, but nothing to be a nuisance. He was very much all other blowpipe tests failed; the lead in the bronze pleased with the whole thing, and thought that when was overlooked by an experienced chemist.-American little improvements were made in the way of charging, by Chemist.

a hopper on the top of the furnace probably, and also by the alteration of the gear, so as to draw the charge out through a slide in the furnace bottom, a great deal of time

would be saved, and he should think that probably University of Michigan.-We have received an ac. instead of their getting three batches out in the twentycount of the course of study pursued in the laboratory of four hours, there would be no difficulty in getting out analytical and applied chemistry in the University of four. He would be very much disappointed if, in the Michigan: also a list of the professors, among whom furnace his firm had now ordered and were proceeding to we find the well-known name of Dr. A. B. Prescott, a erect, they did not get out 100 tons per week. list of the works used as authorities, &c.

Mr. NEWALL said he went over to Middlesbrough and

ence.

28 Newcastle-upon-Tyne Chemical Society. { CHEMICAL NEWS,

1875. saw the furnace at work and was very much pleased with Mr. Jones added that the machinery of it was described it, and thought it did the work very well. Of course they to him, but it was not till his return home from Sicily a all knew they were very much at the mercy of workmen few days ago that he was aware the furnace had been now-a-days; and at Washington they had had the same patented. The main principle of their patent was simply cause of complaint which they had had at Middlesbrough. what had been described by Mr. Pattinson-that they He regretted that Mr. Clapham had not informed them did the whole of the operation at one time. They comwhat steps had been taken previously in the same direc- menced and finished the operation, as it were, at one tion. If the records of the Patent Office were examined charge, and thus saved the labour of the twofold operation it would be found that some twenty-seven years ago Mr. of having first to decompose the salt in one vessel, and William Pattinson, of the Felling, took out a patent for then afterwards transfer it into another vessel to be apparatus almost identical with that patented by Mr. finished, which, to his mind, would render the furnace Jones. The difference was very slight; and if Mr. of Mr. Pattinson, even supposing it had been applied to Pattinson's plan was examined it would be found that it decomposing, so costly to work as to very largely, if not had been apparently much more well considered than the entirely, nullify the benefits to be obtained in their patent specification of Mr. Jones. The drawings attached to by cheapening labour, Mr. Pattinson's specifications were working drawings; in Dr. LUNGE said he had not seen the patent of Mr. Wm. the other they were rather the reverse ; but Mr. Pattinson Pattinson, but he was informed that Mr. Pattinson disshowed clearly that his plan could be carried out for these tindly disclaimed the use of revolving machinery in the furnaces. He had proposed two pans, and of course acid pans, and that constituted a very important differwould do double the work in the same time that was done Of course, by that plan the breakage of the pans in one, or very nearly so; but the two processes appeared would be very much what it is at present. to him so identical that he could not conceive a patent Mr. Mond said he gathered, from what the several taken out for this process now. The whole of the speakers had said, that the work in this furnace must be mechanical arrangement for the operation in Mr. Pattin- essentially different to the ordinary pan.

Both Mr. son's plan was complete. He had gear which drove the Clapham and Mr. Jones remarked the evolution of the stirrer at a certain speed during the process of decomposi- gas was constant, and he also gathered from Dr. Lunge, tion, and when that was completed he reversed the in conversation, that the mass never got into a solid state. mechanism by a clutch and drove the stirrers again at If that were so, he should wish it to be explained; befour times the speed, so as to expel the sulphate at the cause, in that case, it was not only a new furnace, but an end of the operation four times as quickly as it was stirred ertirely new process in making sulphate, and appeared up before. He thought it was worth looking at as a to him to be a very important innovation. Might he ask better contrivance than the one before them ; but other- Mr. Jones to explain if he was right in this supposition? wise the two plans appeared to him to be identical.

The President thought that at one time, in the beMr. H.L. PATTINSON said he imagined that the essence ginning of Mr. Jones's experiment, the mass was fluid at of Mr. Jones's plan in opposition to his cousin, Mr. the commencement of the batch. William Pattinson's patent was this—that the whole Mr. Jones-Not very fluid. The sait took the acid operation was completed in one pan and furnace.

quickly. Mr. GLOVER said that as Mr. Newall had mentioned The PresidENT—You added the salt very quickly? the patent of Mr. Wm. Pattinson he might say that he Mr. Jones--Yes. happened to be at the Felling at the very time the plan Mr. Glover-Have you ascertained accurately the was brought out and worked. He was there until it was percentage of sulphuric acid you used on the salt? discontinued, and he tested the products during the whole Mr. Jones said that Mr. Dyson, manager for Messrs. of the time. Unfortunately Mr. Wm. Pattinson did not Muspratt, Bros., and Huntley, was over at their works carry out his process to the successful issue which Mr. last week, and took charge of the furnace while he was Jones had done, and he thought that Mr. Wm. Pattinson there. He was allowed to do what he liked with it. He would be the first to adm

that that constituted a very weighed one charge of the materials taken, and the results strong claim to the patronage and sympathy of the trade. were as follows:- Common salt, 3 tons io cwts.; sulphuric He recollected that at that time Mr. W. Pattinson's main acid of 140°, equal to 2 tons 17 cwrs. 3 yrs. of 170°. object was to work balls. He worked the furnace for Mr. CLAPHAM –What percentage ? many months as a ball furnace. His great d fficulty at Mr. Jones said he had not worked it out, neither had that time was not so much keeping up the motion and Mr. Dyson, but it was 140° acid, equal to 2 tons 17 cwis. working the material well, as to get a material for the 3 qrs. tools which would stand the corrosive action of the sul- Mr. GLOVER-Of oil of vitriol ? phides. As Mr. Newall said, the machinery which was Mr. Jones-Yes. The finished sulphate which he got contrived and executed was almost perfect-the action of out he weighed at 3 tons, 15 cwts., and estimated that it was perfect. Mr. Pattinson saw it was necessary in he had left 5 cwts. of sulphate of soda in the furnace, applying it to a ball furnace, where the temperature was making the total weight of sulphate of soda produced 4 so high, to have a cooling apparatus, and he believed Mr. tons. He could not get it all out; it was drawn out by a Pattinson specified water, though he used air. But he hand rake. should think that at least twenty-five years had elapsed since Mr. Hill said by that Mr. Jones would make out that the experiment was abandoned, and he thought that both he had used 82.5 per cent of acid of 170°, and got 114 per morally, and even legally, Mr. Jones's patent deserved cent of sulphate upon the salt charged. their support, and he believed that legally it would obtain Mr. Jones said he had not worked it out. it.

Mr. Hill said this was what the figures which Mr. Mr. Jones said he was very glad Mr. Newall had Jones had given brought out. There was just a doubt named this matter, because it gave him an opportunity about the 114 per cent of sulphate on the salt charged, of explanation. His friend Mr. Hugh Lee Pattinson because the general experience on the Tyne led to a very was himself over at their works amongst the first to see much lower result, unless the salt was very dry. the furnace in operation, and at the time he told him Nr. JONES—The sulphate obtained was 4 tons. of the furnace which had been designed by his relative, Mr. Hill-Do you know the moisture in the salt ? and also the use to which it had been applied; and he Mr. Jones-No; but I think it was dry salt. You gathered from Mr. Pattinson's remarks at that time, that could not tell accurately from one batch. the main, if not the sole, use of this furnace was for Mr. Hill-That would account for a high percentage carbonating.

of sulphate. Mr. GLOYER-We tried it for carbonating, but chiefly Mr. Jones—There are no fluxings in this process. for balls.

There is no possibility of any loss. I have not worked it

to go

CHEMICAL NEWS,}
Newcastle-upon-Tyne Chemical Society.

29 out in percentages. These are Mr. Dyson's results of his twenty-four they would have a further gain on the whole own work. He was allowed to have charge of the furnace result. So that dealing simply with practical matters, he for three days and two nights to do what he liked. believed they would be able easily to get up to 100 or 120

The President said the question which Mr. Mond tons. Of course there would be improvements made from wanted answered was this:-In what condition the salt time to time in this furnace. Some people still conand sulphuric acid were mixed together? Was all the sidered that over-head gear in matters of this kind was salt put in at first, and a small quantity of acid added better than under gear. These were inatters which only from time to time till all had been added? Or were the time could work out, at present what would suit one salt and acid put in in small quantities?

person's practice would not suit another's. For instance, Mr. Walsh–We put in two tons of salt first to cover when you brought the salt overhead it was more conthe pan bottom, and then turn on the acid tap, running venient to have under gear; under other circumstances it the acid in in about twenty minutes, and then throw in would be more convenient to have overhead gear. But the remainder of the salt.

these were mere matters of detail, and he thought they The President—Is the whole of the acid put in at would be able to arrive at satisfactory conclusions if they once ?

satisfied their minds on the chemical portion of the work. Mr. Walsh--Yes; it takes twenty minutes to run in, Mr. PATTINSON, with respect to the wear and tear of in 5 ton charges, and while the acid is running, the rest of the furnace, said, of course he had no experience, and the salt is put in.

probably no one had any experience, because it had not Mr. GlOver-The batch is never Auid ?

been in operation long. It was a most vital point, and Mr. Walsh-Well, it is in what you may call a thick time only could clear it up. Perhaps Mr. Jones would pulp. It never becomes thin as in the ordinary decom- give them any results they had arrived at. posing pan. It is pasty and stiff.

Mr. Jones said there was not much to be said upon Dr. Lunge said he noticed specially the point which that point. But the first furnace they put up was put up Mr. Mond had raised. It never became Auid, and there with a very slight pan; he thought the metal would not was not the slightest tendency to boil over. He asked if be more than it inches thick. That pan was soon they used any tallow, and they said no.

cracked, for the reason that all the work had been very Mr. CLAPHAM, in reply to Mr. Mond, said the sulphuric home-made, and the pan put up too close to the fire ; it acid was very strong, and there would not on that account was simply cracked by the heat of the fire, for being set be such a liquid mass in the furnace as if it was a very upon pillars the radiation of heat caused unequal expanweak acid. The batches he saw worked were not what sion. But, in the pan which he had described, which had he would call Auid. They were sufficiently pasty-he been in regular work since last November, there was no thought that was the correct term to use—for the knives appreciable wear and tear to this day. It had been carerough.

fully examined and measured in every part. There was Mr. Goodman thought he would not offer any observa- an air-way between the edge of the pan and the fire, and tions as

to theory, because what he could say was therefore the fire had no direct effect upon it ; and gentlesiinply as to practice. He would much rather say some- men would see that when there was no bottom heat going thing about the machine after trial. He thought a great under the pan, and heat passing over a considerable deal of credit was due to Messrs. Walsh and Jones for the distance above the surface of the pan, there was really way in which they had worked out his furnace. He very little risk of its breaking. He did not know what thought a great deal of time was lost between the Alling might be the life of a pan; it would be mere speculation in of the salt and the withdrawing of the charge. That to give a guess at it. But there was no visible wear and was of course merely a mechanical operation which would tear in the pan at this day, which was begun last probably require a little time to work out. He believed Noven.ber. With regard to the internal machinery, he that the charge had taken five and a half hours to work, had already stated, that while it was of wrought-iron and if it took from eight to nine, he could see that it must there was a tendency in it to bend, especially when the be either from the laxity of the draught or the long time charge became of a thick pasty state. The wrought-iron it took to feed the salt in and get it out, because it some- then having a considerable strain upon it, the arms were times sticks a little to the bottom. But these were

apt to bend a little out of shape. That, however, had not matters of detail, and he had no doubt that an hour and a been observed since the wrought iron arms had been half, or something like that, ought to be saved on each replaced by metal arms, and that was the reason why the batch in twenty-four hours, so that practically he had no original surnace had been stopped, in order to have those doubt they could turn out 20 to 25 per cent more sul. wrought iron arms taken out and metal arms put into it. phate with a more carefully considered arrangement. There was no difficulty whatever in working it with metal There had been an objection raised to the bottom door, arms of sufficient strength, and with metal scrapers and but he believed that the principal objection to the arrange ploughs; and the wear was reduced practically to that ment was that it was a sliding one, and that if the door upon the scrapers, and which was really very little. They stuck they could not get at it. There was no objection to only kept one smith at that class of work in their own the drop door, it was simply the sliding door ; and there works, and he really had nothing to do at this machine had been a doubt expressed by some parties as to whether now. The smith used to be kept going constantly repair. a bottom door could be made tight. He believed Mr. ing the tools for the old decomposing pot. Walsh's practice went to show it could be easily made The President said the matter had been pretty fully tight, and that there was not any doubt as to the tight. discussed, but one point had not been made very clear to ness of the bottom door in his case; but as he said the his mind, and he thought it would be very advisable to simple difficulty was to get the slide out if it was stuck in have information upon it, which would perhaps be forththe bottom. But these were all mechanical arrangemenis coming at the next meeting—that was, as to the exact which he would rather not linger upon at present. At a quantity of hydrochloric acid which was produced. Not future period they would no doubt have the opportunity of only did they want to know the kind of condensation seeing the revised furnace for which he had drawn out the which had taken place, but they wanted to know how working plans. In a very short time one or two manufac much muriatic acid had been obtained from a certain turers would have them in work on the Tyne, and he was quantity of salt decomposed. That had not been very clearly quite confident that the eighty tons which he thought Mr. stated by Mr. Jone and probably, as he said, they had Clapham spoke about in his paper could, first of all, be no data to make the calculation. But he hoped that at increased if the pan was about one-fifth more capacity the next meeting Mr. Jones would be prepared to state than that of the pan which they were at present working. | how much hydrochloric acid was obtained from a certain From one-fifth on eighty they would see what the result amount of salt. Whether Henderson's process was likely was, and by gaining about three or four hours out of the to supersede all the others, and sweep the present plant

30
Analysis of Manganese Ore.

{ ,

July 21, 1876. off the face of the earth they could not tell; but it was

DR. J. W. HEARDER, F.C.S. quite clear, he thought, that Messrs, Jones's furnace was a very great improvement on our present decomposing

To the Editor of the Chemical News. plant, and they ought to be very much obliged to those Sır,—Mr. Mendola, in his attack on Dr. Hearder, has, gentlemen for bringing before them such an important I think, entirely mistaken his grounds. The letters F.C.S., discovery. There was evidently a very material saving F.R.S., or F. any other S., show and mean nothing what. of labour and labour of a disagreeable kind, which was a ever except that the holder is supposed to have some very important consideration in these times. He had interest in the work of the said s., and that he is held in great pleasure in moving that a vote of thanks be given to sufficient estimation by the members to be permitted to Mr. Clapham for his paper, and to Mr. Jones and Mr. join them. I have not the smallest doubt that this is fully Walsh for attending there to give them the explanation of and perfectly understood in its proper sense by every the working of their furnace.

person of very ordinary intelligence. What little position such a qualification as this gives is undoubtedly made use of one way or another by almost every member of every

Society in existence. It may not be that every one sends CORRESPONDENCE.

it out by thousands, but even the leaders of the Chemical Society are not free from this fault, if it is a fault. To

print it on the title-page of a book, or in fa&t anywhere ANALYSIS OF MANGANESE ORE. else (except in matters strictly connected with the Society),

is not appreciably different to printing it on a circular. To the Editor of the Chemical News.

It would appear that Mr. Mendola has an exalted idea of Sir,--From his letter (CHEMICAL News, vol. xxxiv., p. 19), the possible value of the Fellowship of the Chemical I fear Dr. Phipson has not understood' my query on the Society, , If a brass farthing is polished, and held at a determination of the oxides of manganese, and I must respectful distance from the eyes of the public, perhaps therefore request the opportunity of explaining myself some may mistake it for a sovereign; but I think to atfurther. As Dr. Phipson is no novice I erroneously tempt to persuade the educated classes that the Fellowimagined that he would at once appreciate my meaning.

ship of a Society is any qualification is an insult to their In the CHEMICAL NEws (vol. xxxiii., p. 243) Dr. Phipson common sense neither Dr. Hearder nor Mr. Griffin would published in your columns a very elaborate analysis of a

be guilty of. I am not aware that the Fellows of the sample of manganese ore, which your contributor had Royal or any other Society attempt to hide their light found to contain 72'17 per cent of MnO2. There was an

under a bushel if it can be exhibited to their own moral additional quantity of manganese beyond the amount

or pecuniary advantage, and the same remark applies to present in the above form, and this Dr. Phipson assumed the whole class of what may be called the Societies of to exist as Mn203, 6'20 per cent being thus accounted for Specialists. Men of business, of which a large propor

In my last letter, I, in effect, asked if Dr. Phipson had tion of the Chemical Society is composed, do their adverany means of distinguishing this Mn203 from a mixture tising in their own way; those who are not men of or combination in atomic proportions of MnO and MnO2 business simply do it in another way amongst their friends (=Mn2O3), and I receive the unsatisfactory answer that and acquaintances, and make, or think they make, a moral Dr. Phipson " discovered the manganic oxide (Mn2O3) in profit instead of a pecuniary one. When a Fellow of any a very simple manner, namely, by determining in the first Society makes it known that he is one, as a matter of place the total quantity of oxygen, and in the next the business, he simply takes an indirect means of giving total quantity of manganese. These two data are quite references to his personal friends who have signed his sufficient for the purpose.”'

application,-i.c., the fact of his being a member is, to a As well might Dr. Phipson attempt to distinguish very limited extent, a moral guarantee that he is not abacetate of ethyl from butyric acid (both of which have the solutely unknown. If the Chemical Society transforms same empirical formula) by determination of the carbon itself into a strictly professional Club, and goes out of and hydrogen as

think he can te!l Mn203 from business in the printing and publishing line except for its MnO+Mno, by merely ascertaining the proportion of own members, then the use of the letters F.C.S. by the manganese and oxygen, for a glance will show that the holder, except in matters striatly connected with the percentage composition is the same in each case.

Society, might be considered improper. Unfortunately, as a provincial chemist, the French It is an open question whether those who are raising edition of H. Rose's chemistry is not readily accessible, the cry of discontent are not a few who—not being but I think the author would scarcely thank Dr. Phipson eligible or qualified for admission to the Royal Society for fathering such a method on him.

wish to polish their farthing up to the utmost limits, and My question was asked in perfect good faith, as I really try to make it look like the real thing. To my mind the thought there might be some means of arriving at the only way to do this will be to admit all as Associates at information sought. As it is I will ask your correspond- first, and afterwards make the Fellowship conditional on ent a few other questions, and challenge him to reply.

the contribution of original papers or work to the Society. 1. How does Dr. Phipson know that the 6'20 per cent

This revolution might include the whole of the existing of Mn203 which appears in his analysis was not made Fellows who had not contributed any original work since up of 3'41 of MnO2 and 2.79 of MnO?

their election. The rule might be that Associates should 2. If he does not know, how did he distinguish the 3:41 be elected as Fellows on the publication of any Paper of per cent of MnO2 from the 72'17 admitted to be present?

theirs in the Transactions after it had been accepted and 3. What process was employed for the determination of read at one of the meetings. This would give the Fellows the main quantity of MnO2, and would not the amount

a slightly better position than they now hold, and would found include the 3:41 per cent, assuming the latter to

no doubt considerably increase the amount of original have any existence?

work published, more especially if all Fellows after their 4. If the result of the determination of the MnO2 election were liable to be called on for Papers at intervals (=72*17) represents the total quantity of that oxide pre- of say not less than one year. This would do what nei. sent, must not the remainder of the manganese necessarily ther blackballing nor raising fees could do, and would be have existed as MnO and not as Mno+MnO2(=Mn203)? practically equivalent to an examination without its weak

5. If the last question is answered in the affirmative, points. The position of the Society can be improved has not Dr. Phipson counted his oxygen twice over ?-

better without the use of personalities, and if the disI am, &c.,

cussion of the matter is left entirely to the Council it will

ALFRED H. Allen. be better for all parties concerned. When discontented Sheffield, July 15, 1876.

members descend to personal attacks in public journals,

CHEMICAL NEWS,

Chemical Notices from Foreign Sources. July 21, 1876.

31 the Society must be getting in a bad way, and it is time has been made. This theory, as we know, is subdivided for the Council to take the matter in hand.- I am, &c., into various doctrines, of which a very complete and lucid

Thos. FLETCHER.

exposition has been given by M. Bertin in the June num. Warrington, July 18, 1876.

ber of the Annales de Chimie et de Physique. The capital objection which mechanicians oppose to these different

explanations is, they are all reduced to admit, that the CHEMICAL NOTICES FROM FOREIGN

radiometer is an instrument of reaction. But in such

apparatus, having regard to the impossibility of the motive SOURCES.

power being rapidly produced with a sufficiently constant

intensity, there ensue merely rotations accompanied by Note.-All degrees of temperature are Centigrade, unless otherwise retardations and bounds far from being reconcilable with expressed.

the perfect regularity of the radiometer. Moreover, the

theory in question expressly requires that there shall never Comptes Rendus Hebdomadaires des Seances, de l'Acade nie, be an equilibrium of temperature between the gas in the des Sciences. No. 26, June 26, 1876.

case and the discs of the radiometer. But how are we Maximum of the Possible Repulsive Power of the to admit that in every experiment this equilibrium is not Solar Rays.-M. G. A. Hirn. The attention of the ultimately established ? Moreover, the rotation ought to scientific world has been latterly drawn to the singular stop at last instead of maintaining itself indefinitely at the phenomena which Mr. Crookes has studied with the same speed. The author then cites certain experiments radiometer. The conclusion which has presented itself to difficult to explain by the supposed movement of gases in the mind of many is that these phenomena are due to an

the interior of the apparatus. Thus the instrument was impulsive action of the luminous rays, and that it is thus heated nearly to redness, when it commenced turning, but demonstrated that light is a movement of ponderable the rotation was sensibly accelerated by the momentary matter. Nevertheless, the phenomena discovered by presence of a single flame, which joined its action to that Mr. Crookes have been elucidated, if not in their cause, of the radiant heat. An apparatus was constructed with still in their form and their starting-point. The ingenious discs exclusively polished. On throwing a pencil of solar counter-proof to which M. Arthur Schuster has submitted rays upon one of the two hemispheres oi the glass case a them places it beyond doubt that it is by no means the perfect rotation was obtained, without interruption, and direct action of the rays emanating from the luminous as free and rapid as with an ordinary radiometer fully exsource which determines the movement of the discs of the posed to the light. The author bases his explanation of radiometer, but that the repulsive power here called into the phenomena upon a mechanical action of the “ether" play has its seat in the walls of ihe transparent vessel perpendicular to the direction of its rays of propagation, which serves to contain the mill, and that this power is and not in the same direction as these rays. This interset in action by the pencil of rays directed upon the pretation is calculated to calm the legitimate disquiet of apparatus. As the true explanation of the totality of the the partisans of undulation. In Germany there is a leanphenomena has not yet been given, and as the hypothesis ing to an explanation based upon electricity. They rely of the materiality and of the impulsive force of light will upon the experiment that when a radiometer with discs probably not soon be abandoned, the author thinks it exclusively polished, and where one of the hemispheres of useful to submit this hypothesis to the test of the method the case is traversed by a continuous electric spark, the of successive elimination. Mr. Crookes has calculated instrument takes a rapid rotation always opposite to the the apparent repulsion exerted by the solar rays at i grm. direction of the spark, this direction being understood per square metre. This pressure is more than one thousand according to the common convention. "In any case the times greater than the maximum value possible for re- radiometer of Mr. Crookes seems to us a serious instruflecting bodies, and more than two thousand times superiorment, and not a paradoxical apparatus destined to enjoy to the maximum value possible for absorbing bodies. We an ephemeral scientific repute and then to rank as a mere may, then, affirm that the phenomena which Mr. Crookes physical amusement. Its experimental study, pursued has made known are nowise due to the effect of an im- under all modifications and with an indefatigable persepulsion of light, and do not imply the idea of mass of verance, will certainly lead to important results as to the density as regards radiant light and heat. However care- mechanical properties of the ether.” fully the vacuum in the vessel enclosing the radiometer or Process for the Manufacture of Soda from Seaweed torsion balance may be made, there remain, nevertheless, by Endosmotic Lixiviation.-M. L. Herland.—The quantities of gas or vapour relatively enormous. The author gives the following reasons for the depressed state maximum pressure which the solar radiation can exert of the seaweed industry: the weed is collected indiscrimupon 1 square metre of absorbing surface is o‘0004157 grm.: inately without regard to its greater or less richness in let us suppose that the discs of the radiometer are 10 square iodides or other useful salts. The weed destined for incentimetres, the maximum pressure upon them will be cineration is dried on the shore in the open air, whence 0'000004157 grm., or a little more than 100 fouth of i grm. results a decomposition and a loss of salts from the spray The slightest agitation of the small quantity of gas re- of the sea, dew, rain, &c. The process of incineration maining in the apparatus will produce upon the radiometer itself is the main cause of the weakness of the product in pressure comparable to this. However transparent may iodine, as a certain quantity is volatilised, but it is chiefly be the glass case of the radiometer, it still absorbs a part to the siliceous sand mixed with the weed that the great of the calorific or luminous rays; one of its surfaces is loss is due. In fact, silica at high temperatures reacts heated more rapidly than the other. This inequality of upon the iodides, producing alkaline-earthy silicates, and temperature necessarily determines electric polarity, or eliminating a certain quantity of iodine. The author, the manifestation of static electricity. The vacuum, it is therefore, proposes the following method :—The fresh said, is so perfect that the electric spark cannot traverse weed is placed in baskets of iron-wire, moved by a turning the apparatus. But electric attractions and repulsions crane, and steeped in a series of vats containing about traverse the vacuum. However feeble may be this cause

50 kilos. of good quicklime per cubic metre of water, and of attraction and repulsion, it may nevertheless have a arranged in circular batteries. The weed passes in suc: considerable value in comparison with our maximum of cession from vat to vat, and is exhausted of all its useful 0'000004157 grm.

salts. The same series of successive immersions is purNew Experimental Considerations on the Radio-sued with fresh weed until the first vat marks 4'3° to 45° meter of Mr. Crookes.-M. A. Ledieu.—The author's on the hydrometer (pèse-sels, probably a Baumé's glass experiments become less and less favourable to the theory adapted for saline solutions). During this operation a of the apparatus based upon the movements of gases and double exchange takes place between the weed and the vapours remaining within the glass case after the vacuum lime-water, ty means of endosmosis. The time of steeping

« PoprzedniaDalej »