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THE CHEMICAL NEWS.

Vol. V. No. 131.-June 7, 1862.

THE PATENT LAWS.

The whole reasoning of Sir Hugh on this part of the On last Tuesday week. Sir Hugh Cairns brought forward subject is so well answered in the Times that we shall in the House of Commons his long-threatened motion

make no excuse for quoting the passage. “The vice of for a Royal Commission to inquire into the operation of too many inventions now patented,” says the Times, " is the Patent Laws. It is needless to say the motion was not their want of utility, but their want of novelty, or carried without a division. The whole policy of the

rather their suspicious resemblance to some other conPatent Law will now be brought under consideration,

trivance already in use; and that is a point quite capable and the opponents and supporters of grants of monopoly

of being sifted. Nothing can be more impolitic than to will have a fair opportunity of urging their various

grant a lucrative and exceptional right as a matter of opinions. Our own views on the subject may be stated

form, on the chance that, if it should have been granted in a very few words. We believe it is only right that

in error, some one will move for its revocation, though an original inventor should be secured, as far as possible,

| not, perhaps, till after it has been transferred by assignsome reward for his ingenuity; and this perhaps is best

ments and deeds of licence to a dozen different persons." accomplished by giving him for a time à monopoly in | And so, we may add, been proved to be of sufficient his invention. But we have no doubt that we shall | value to make it worth disputing. Nobody would think fairly state the opinion of all disinterested readers when of going to law about a “worthless or a trivial patent ;”. we say that but one claim for a monopoly should be

| but there are people who would inove all the Courts at allowed, and that is, the novelty or the originality of

Westminster to upset a valuable one. And then, argues the invention. This satisfactorily established, the right

Sir Hugh, scientific men are so sceptical and prejudiced, to protection, we think, is indubitable. But it is clear

that they cannot be trusted to give an opinion as to the that, proceeding on this idea, an entirely different method novelty or usefulness of an invention. Sir Humphry of granting patents must be adopted. At present, as Sir Davy, he says, did not believe in the possibility of Hugh Cairns stated, the only investigation which alleged lighting houses with gas, and had he been acting as a inventors undergo before patents are granted is conducted judge, he would have condemned that invention as useby the law officers of the Crown, and is confined to the less. We do not believe that Sir Humphry would have descriptions in the specifications. Of the novelty or done anything so absurd. If an inventor had come usefulness of an invention they, of course, can be no forward professing to accomplish what had before been judges. As regards the usefulness, about which so much

deemed impossible, Sir Humphry Davy, like a sensible parade is made in a patent, we believe that that may be man, would have considered it the strongest ground for Jeft entirely out of the question. If an invention is not

granting him a patent, and would have left him to useful, there will be small advantage in obtaining a

demonstrate the practicability of his scheme when he patent for it. The novelty, however, is a matter had been fairly protected. Sir Humphry might have deserving some investigation, and this could only be con-objected, -he did so, in fact, to the lighting of a house ducted by persons well acquainted with the subjects

with gas as dangerous, but he would never have conconcerned. Speaking as a lawyer, Sir Hugh is of course demned the invention as useless. opposed to any preliminary scientific investigation. This, Taking chemical patents as illustrations, and not being to a legal mind, we have no doubt, would appear the lawyers, we believe that the manufacturing public would height of absurdity. It is so much more simple and

be most easily disembarrassed of worthless and trivial reasonable for any one to get a patent revoked by apply.

patents if the specifications of the alleged inventors were ing for “a rule to show cause, or something of that

submitted to a competent chemical authority before the sort, by which a person might be called on to justify his patent was granted. It would be invidious now to patent, and thus the air might be cleared, and the mention special instances; but any reader of the manufacturing public would be, at a small expense, dis CHEMICAL News, or any person having much acquainembarrassed of worthless and trivial patents." No

tance with chemical patents, will remember numerous doubt of it, if any one would take the trouble ; but

cases in which they ought never to have been granted. unfortunately such a “ short and simple mode” might The ideas in these patents have not the least show of have another effect different to that contemplated.

novelty, they may even be found in a familiar manual; Probably if Sir Hugh had set his wits to work to see in

but an insidious wording of the specification and the what way a grasping and litigious capitalist might most

claim opens the matter for litigation if it should ever easily rob an inventor of the fruits of his ingenuity and

turn out worth disputing, and most manufacturers, industry, he could not have proposed a better scheme

unless very wealthy, would rather pay for a licence than than the one suggested above. Most likely in the end it defend an action for infringement.

| would be found quite as expensive to justify a patent as

With all that fell from Sir Hugh Cairns respecting to prosecute for infringements; and another legal

the tribunals for the trial of patent cases, we fully agree. reformer coming a few years after Sir Hugh, would have

He seems inclined to accede to the proposal for scientific equally gross instances of expensive litigation to quote,

assessors, which we advocated some weeks ago, but exand, we believe, with greater wrong done.

| pressed no decided opinion on that point. It is hard to

CHEMICAL NEWS,

310

On the Presence of Rubidium in Certain Vegetable Substances. {C7

see why, if scientific assessors may advise a judge in of rubidium, but not a trace of lithium. Coffee is much the trial of patent disputes, scientific commissioners may richer in rubidium than tobacco. not advise the Attorney-General in granting patent 3. Grapes (crude tartar).-M. Kestner, of Thaun, rights, except, by the way, that the latter proceeding has kindly sent me, at my request, some mother-liquors might perhaps render much of the former impossible.

obtained in the treatment of crude tartars. These liquids were freed from organic matters and foreign substances

which they contained, and the residues then submitted SCIENTIFIC AND ANALYTICAL to spectral analysis. I am able to state definitely that CHEMISTRY.

they contain rubidium, but in very small quantity.

It appears certain from these facts that rubidium is

one of the most widely distributed simple bodies in On the Presence of Rubidium in Certain Vegetable nature. The most different vegetable bodies from the

Substances (Beet-root, Tobacco, Tea, Coffee, Grapes), most distant localities remove it from the soil. Moreby M. L. GRANDEAU.

over, it is evident from my researches that the presence On the 24th of February last, I had the honour to com of rubidium is not necessarily allied with that of lithium, municate to the Academy the results of my researches as might have been imagined from the analyses of on the presence of rubidium in the salts from beet-root, minerals and waters in which M. Bunsen has discovered and in the mother-liquors obtained from treating them this metal. I ought to add that several vegetable bodies for the extraction of chloride of potassium. Since then of which I examined the ashes appeared to contain no I have actively pursued this research, both in the labora-rubidium, although many of them were rich in potash. tory of the upper Ecole Normale and also in the im- I may especially mention as instances the colza, the portant factory of M. Lefebvre, distiller at Corbehem, cacao, the sugar-cane, and some species of fucus. who has kindly placed at my disposal the substances The dissemination of the new alkaline metal being necessary for extracting chloride of rubidium on a larger placed beyond doubt by the researches of which this is scale.

a résumé, it is of great interest to examine with this Thanks to this assistance, I now possess 400 grammes particular object the soils in which the above-mentioned of pure chloride of rubidium, about half of which has vegetables grow. With this view I have undertaken been prepared at the factory at Corbehem, according to experiments and analyses, which I am pursuing as my instructions, by the assistance of M. Martel, a skilful rapidly as the long and delicate character of these young chemist attached to M. Lefebvre's establishment, investigations will allow.- Comptes-Rendus.

When presenting to the Academy, at a subsequent sitting, the new salts of rubidium which I had been able to prepare from the pure chloride at my disposal, I

On the Production of Nitrate of Methyb, will describe the processes which I have employed for the extraction of the chloride, and will show by the

by M. CAREY LEA, of Philadelphia. aid of a few figures that the quantity of rubidium For the production of nitrate of methyl but one process annually removed from one hectare of land by beet-root appears to have been proposed, and that is to be found is an amount not to be neglected from an agricultural in all our text-books, English, German, and French. point of view.

Two parts of powdered nitre are to be distilled in a I now propose to submit to the Academy some new capacious flask with a recently prepared mixture of 5 results, proving the great dissemination of rubidium in parts wood spirit and 10 oil of vitriol. Judging from nature. Having found the new metal in the salts from the reactions of ethylic alcohol, it did not appear to me beet-root, which it is known are very rich in potash, it probable that such a proceeding could succeed. It was seemed of interest to seek for it in other vegetable sub- tried, however, and with the following results. stances, which, by the readiness with which they remove The substances were placed in a flask capable of conpotash salts from the soil, more or less approach beet- taining twenty times their united volume, which was root in this respect. I will confine myself in this connected with a Liebig's condenser by a wide delivery extract to point out the analytical results which I have tube. For a few minutes no action was perceptible, but obtained, omitting the methods of separation and analyses it soon set in, with rapidly increasing violence. Torrents given in my memoir.

of gaseous products with deep red fumes of oxides of 1. Tobacco.--I have at present only examined the nitrogen were evolved, and presently the apparatus blew ieaves from Kentucky and Havannah. M. Schlesing, up with a loud explosion, and had not due precaution Directeur de l'Ecole d'Application des Tabacs, has been been taken with a view to a possible unpleasant congood enough to evaporate to dryness in his laboratory a clusion, personal inconvenience might have resulted, for certain quantity of water which had been used for the the 3-litre flask was shattered into very small pieces, prolonged washing of Kentucky leaves. The ignited which were thrown to a considerable distance. The residue was tolerably white, spongy, and very rich in quantities operated upon were small; 50 grammes of potash. On spectral analysis this residue gave the methylic alcohol and proportionate quantities of the characteristic lines of lime, lithium, potassium, and other substances. No heat was applied. rubidium. The quantity of lithia was very slight. It is scarcely probable that the gases were evolved in There was, on the other hand, a notable quantity of such quantities as to have caused the explosion. It rubidiurn.

seems more likely that the heat generated by the reLeaves from Havannah, best quality, were carefully action was sufficient to raise the temperature of the burnt; their ashes gave me on analysis results iden | interior of the flask to 150° C., at or below which point, tical with those obtained from the Kentucky leaves. according to Dumas, the vapour of methylic nitrate

2. Coffee and Tea.- Coffee and tea completely and explodes. carefully incinerated left ashes rich in potash. An I have had no difficulty, however, in preparing this examination of these ashes, after appropriate treatment, ether by a different process. By dissolving a considershowed in each of these products considerable quantities able quantity of urea or nitrate of urea in methylic

CHEMICAL NEWS}

New Method of Estimating Alkaline Hijdrates, &c.

June 7, 1882,

311

alcohol, it supports the action of nitric acid with the Stated metallic copper is then separated by filtration and utmost facility. The following are the proportions which the liquid slowly evaporated. If, during evaporation, I have employed.

the neutral solution of sulphate of cadmium should Into å retort of the capacity of a litre, 200 C.C. of deposit a small quantity of sesquioxide of iron, which purified wood spirit are placed, and about 40 grammes not only constitutes an impurity, but gives the salt a bad of nitrate of urea are added and heat applied. When appearance, it is necessary to expose the solution to the solution has nearly taken place, 150 c.c. of nitric acid, atmosphere until all the iron which it may contain has free from the lower oxides of nitrogen,* sp. gr. 1.31, are been eliminated, which is accomplished when, after a added, and the mixture is distilled to one-third. 170 c.c. second filtration, the transparency of the solution is no of wood spirit and 130 of nitric acid are then added and longer disturbed. To obtain finally the sulphate of distilled to the same point. Finally, 150 c.c. wood spirit cadmium in well-formed crystals, it is necessary to and 110 nitric acid, with 10 grammes of nitrate of urea, acidulate the solution slightly with dilute sulphuric acid. are added, and distilled to the same point as before. It -Journ, Md. Col. of Pharm. is useless to carry the distillation further than the point here specified, not that it is accompanied by any inconvenience, but because nitrate of methyl ceases to be l New Method of Estimating Alkaline Hydrates and evolved. The temperature rises very high at the close

Carbonates, and other Compounds of this Class, by of the distillation.

M. PERSOZ. The operation may be carried on rapidly. We are recommended in the text-books to carry off the vapours

In a recent number of the Annales du Conservatoire des very carefully in preparing nitrate of methyl, on account Arts et Metiers a new method of estimating nitric acid of the production of cyanhydric acid as a by-product. I was described, founded on the following facts : In chemical laboratories there is, doubtless, generally 1. Fluorides, chlorides, bromides, and anhydrous rather too little precaution taken than too much against alkaline sulphates are not decomposable by potassic noxious vapours; but in the present case I have care- bichromate heated to fusing point, and even to nascent fully examined the distillate, both in the old process,

red heat. which failed, and in that which I here propose, and í 2. All nitrates are decomposable under these condicould find no trace of cyanhydric acid either by the iron tions. Nitric acid is completely expelled in proportion or the silver tests, or by conversion into sulphocyanide. as chromic supplies its place, and an equivalent quantity Both the ether itself and the watery part of the dis- of chromate is produced. tillate were tested. As, however, it is impossible with- Now, in applying this method to the estimation of out special analysis to know what impurities may be certain commercial salts of soda,-mixed with carbonate, present in so variable a substance as commercial wood chloride, sulphate, and nitrate,—which are frequently spirit, it is difficult to foresee what substances may be sent to the laboratory of the Chamber of Commerce, generated in its decomposition ; but I think I am justi-which salts sometimes contain as much as 19 per cent. fied in concluding that cyanhydric acid is not generated of nitrate, I found that by heating with precaution a by the action of nitric acid upon methylic alcohol; at mixture of these salts and bichromate, taking care not least, not in the presence of urea.

to raise the temperature sensibly beyond the fusion point Treated as above described, 420 grammes of wood of the latter, that the whole of the carbonic acid was spirit yielded a distillate, from which by agitation with expelled without taking the nitric acid with it. solution of salt there separated the very large quantity It is evident that we here have the means of of 300 grammes crude nitrate of methyl. This may be mining through successive losses estimated by weighing subsequently agitated with a little weak solution of car first the carbonic and then the nitric acid. As the loss bonated alkali.

of nitric acid in a well conducted operation corresponds The wood spirit before use should be distilled with exactly with the alkalimetric standard, one more step one-third of its bulk of very strong (almost saturated) I only is necessary to the formation of a rational method solution of caustic soda, to decompose any acetate of of estimating commercial alkaline carbonates without methyl which may be present. This operation must be having to fear, in certain cases, the errors inevitable to performed over the water bath.- Amer. Jour. Science | the employment of the ordinary methods, and owing to and Arts.

the presence of alkaline sulphides, oxisulphides, lime, sulphites, and hyposulphites, &c.

It is easy to understand, and it has been ascertained 4 Quick and Easy Method of Preparing Sulphate of by direct experiments, that potassic bichromate either Cadmium.

oxidises or saturates oxisulphides, sulphides, sulphites, Tuis method, adopted by the author, is nothing more

| hyposulphites, and lime without causing any disengagethan the application of the fact observed in 1792 by

ment. A carbonate, on the contrary, decomposed by Richter, that a metal plunged into a saline solution sub

potassic bichromate occasioned a disengagement of carstitutes itself for the metal, which forms the base of the

bonic acid exactly proportioned to the amount of the

base which retained it in combination. A hydrate salt employed. A quantity of crystallised sulphate of copper, say 100 grammes, is dissolved in water, and a

equally disengaged a quantity of water corresponding piece of cadmium, rather more than is necessary to

to a simple hydrate or to a bihydrate, according to the saturate all the sulphuric acid, or in this case more than

temperature employed., 44:59 grammes, is plunged into the solution. The whole

It only remained to devise an apparatus so to conduct having been allowed to stand for some time, the precipi.

the experiment that the products of the reaction might

be collected. Liebig's apparatus was ready to our hand, * Freedom from the lower oxides is an essential condition of

and this, slightly modified, was employed to analyse the success. That nitric acid is colourless is not in itself a sufficient organic matters. We used then a combustion tube from indication of purity in this respect. An acid which causes the least darkening to a solution of ferrous sulphate is wholly unfit for use in

50 to 60 centimètres long, very slightly curved in the the proparation of either methylic or ethylic nitrate,

centre to a U-form, and bent inversely on both sides, so 312

Paraffin Oil.

( CHEMICAL News, 1 June 7, 1862

as to keep the two extremities horizontal. By one of to the custom of manufacturers of submitting these these extremities the tube was in communication, by mixtures to simple aqueous fusion instead of making means of a small copper cock, with a system of columns them red hot. However, by estimating the base common and tubes furnished with all the agents usually employed to the water and carbonic acid all uncertainty disappears. for freeing the air from foreign bodies ; by the other it! For commercial potash and soda, containing sulphides, was connected with a Liebig's apparatus for retaining sulphites, lime, &c., we use the same processes as with the water and carbonic acid disengaged by the combus-carbonates and hydrates, it being only necessary to know tion of an organic matter. Finally, the apparatus com- how to raise the proportion of bichromate, and, accordmunicated with an exhauster by the intervention of a ing to the nature of the salt, to observe certain precauflask or of a drying tube, to prevent contact of the humid tions.f For the rest we cannot give a better proof of air of the exhauster with the air of the apparatus. this than by citing some of the results of our experi

To sum up, the apparatus is composed of the following ments. parts :

Having at our disposal a commercial soda—a mixture V, an aspirator, serving to circulate air through the of carbonate, bihydrate, chloride, and sulphate-of which apparatus and to pass the disengaged water and carbonic we knew, besides the alkalimetric standard, the exact acid over the bodies destined to absorb them.

proportion of each of the principal ingredients, we A, a system of gauges and tubes furnished with agents selected it on account of its complex nature as the basis necessary for the purification of the air.

of our operations. Submitted to the action of bichroB, a combustion tube containing the bichromate and mate in our apparatus, it yieldedthe substance to be analysed.

Carbonic acid , . , 29• per cent. C, a complete system of tubes for the total absorption Water . . . 55 » of the water and carbonic acid.

These numbers given in sodic carbonate and bihydrate D, a tube of U-form midway between the exhauster

correspond within a few thousandths with the alkaliand Liebig's potash tube, and intended to prevent the access of moist air.

metric standard of this product.

| We treated it in the same manner, but with the addiThanks to these arrangements, it is possible, as will

tionbe seen, to regulate at will an operation of which the results leave little to be desired, if some precautions to

1. Of 50 per cent. its weight of sulphate of lime; we be described further on are not neglected.

collectedMethod of Operating.-In operating upon a carbonate,

Carbonic acid . . . 29.5 per cent. it is sufficient to introduce into the tube B 30, 40, 50, or

Water . . . . . 60 grammes of melted potassic bichromate,* previously 2. Of 5 per cent. its weight of sulphate of soda conmixed with 1, 2, or 3 grammes of carbonate, if this is taining carbonate ; we collected insoluble, but if it is soluble the preliminary mixture is

Carbonic acid . . . 2998 per cent. superfluous.t The tube B being securely connected at.

(The salt not having been dried, the water was not taken its two extremities with the two systems described, we determine the flow of water in the aspirator V, in order

| into consideration.) to produce a current of air in the apparatus, and then

| 3. Of 100 per cent. its weight of commercial quick we heat the tube B. Simultaneously with the fusion of

| lime, containing water and carbonic acid, we collectedthe bichromate the disengagement of carbonic acid begins,

Carbonic acid . . . 312 per cent. which is easily moderated during the whole of the We must not forget that the compounds used in these experiment. The operation is at an end when the whole experiments are with difficulty kept from contact with mass is fused. The increase of weight of the potash the air, from which they rapidly absorb water and cartubes indicate the amount of carbonic acid disengaged, bonic acid, which accounts for any difference in the from which the proportion of carbonate is to be deducted. results. Nevertheless, the numbers obtained prove that

In operating upon a hydrate or upon a mixture of in circumstances as exceptional as those under which we hydrate and carbonate, we proceed in the same manner, operated, and where alkalimetric testing was impossible, only it is necessary to take all precautions, both before our results are not far from exact.-Journal de Pharand after the operation, that no moisture exists in the macie et de Chemie. tube B. Then the respective weights of the water and carbonic acid show the relative proportions of carbonate and hydrate, taking into account the fact that mixtures

TECHNICAL CHEMISTRY. of commercial alkaline carbonates and hydrates are always formed of a bihydrate. This result is attributable

Paraffin Oil: Report on the Quality of Illuminating

Oils sold in Manchester and the Neighbourhood, by * Before being used the bichromate should be carefully heated. When cold it should be placed in a bottle stopped with emery, as it CHARLES O'Neill, F.C.S. absorbs and fixes the aminonia of the air. Notwithstanding the fusion to which the bichromate is submitted, we take the precaution of again

In compliance with a request of the General Committee of melting, just before using it, the quantity required for an operation, the Manchester and Salford Sanitary Association, I have

+ In operating on insoluble carbonates, such as those of lime, baryta, examined a number of samples of oils sold in this town strontia, magnesia, manganese, iron, zinc, copper, lead, &c., it is

and neighbourhood. In all I have examined thirty-two essential, in the first instance, to reduce these salts to a fine powder, by one or other of the methods usually onployed for that purpose. When), on the contrary, carbonates, with potash, sod, or lithia bases, different retail shops. Two samples of paraffin oil I cspecially the two first, are operated upon, this precaution is not only useless, but dangerous, no account of the rapid decomposition which

obtained direct from the Paraffin Light Company's takes place, occasioning projections of bichromate, sometimes reach premises ; and five samples of oil, obtained from London, ing as far as tho first Liebig's tube, if the precaution is omitted of placing at the anterior part of the tube B a piece of ignited amianthus, 1 In operating upon crude potashes and sodas containing charcoal, which has the effect of retaining the projected portions of bichromate, besides the sulphides and oxisulphides, it is indispensable previously and thus preventing errors. The operation finished, that part of the I to wash them, to evaporate the washings, and then to determine tho tube containing the amianthus shoull be heated, so as to expel any weight of the salino inatters thus obtained; the salt being properly water which may have condensed in it.

dried, it is then only that the bichromato can react.

CHEMICAL NEWS,
June 7, 1862. }
Paraffin Oil.

313 Liverpool, and Bradford, were forwarded to me by the lamp. I concluded from my experiments that a temperaParaffin Light Company, and included in my examina- ture of from 85" to 90° might be calculated upon tion.

as often existing in the cistern of a lamp, this high Out of the twenty-five samples purchased in Man temperature being produced by a long-continued burning chester, sixteen were clearly identical with the genuine of the lamp in a warm room, and on a table near the samples of paraffin oil supplied to me by the Manchester fire. Any oil, therefore, giving off a combustible vapour agency, the other nine samples consisted of other kinds and forming an explosive mixture with air at this of oil differing from the paraffin oil and from one temperature must be looked upon as unsafe for ordinary another. Some of them were supplied in answer to a use. I tested the remaining thirty samples, and found request for paraffin oil; three or four purported to be three which gave an explosive mixture at 85° F. American rock oils, and were sold under the names of These are numbers four, five, and sixteen, bought repetrolene, kerosene, and photogene. The whole nine spectively in Liverpool, Bradford, Hulme, and Manwere doubtless various qualities of Americap rock oils, chester. There are, therefore, five samples really and, adding to these the five samples sent by the Paraffin dangerous, and which would require the constant exercise Light Company, I had fourteen samples from the new of care and skill to prevent serious accidents. and extraordinary oil wells in Pennsylvania and Canada ; In order to classify the remaining oils, I submitted the remaining eighteen samples being the home manu the whole of them to a temperature of 100° F., and factured oil sold as “ Young's Patent Paraffin Oil.” found four of them to yield an explosive mixture at

I obtained three of the lamps employed for burning this temperature,—viz., numbers two, nine, eleven, and these oils; they were low-priced lamps, such as are used twelve; three of these were purchased in Manchester. in the poorest sort of houses, but do not appear to differ These oils would be highly dangerous if used in any in any essential point of construction from the more situation where the temperature was as high as 1000; expensive lamps. These lamps are constructed pur. and, though I consider them as unsafe oils, I cannot call posely for burning the paraffin oil; they are not suitable them highly dangerous, because the temperature of 100° for burning the older kinds of lamp oil, nor are they is hardly ever reached in this climate, and never in the safe with very volatile fluids, as naphtha and camphine. night when lights are required.

In deciding whether any of the samples under in- | As a next step, I exposed the whole of the remainvestigation were dangerous or not, I have considered ing oils to a temperature of 120° F., testing the them entirely in reference to the lamp in which they explosibility of the vapour ; three samples proved exare used; some of the oils called dangerous might be plosive at this temperature,-viz., numbers twenty-one, safely used in another kind of lamp, and the safest of twenty-five, and twenty-eight, purchased in Salford, them would be dangerous if used in a moderator or Hulme, and Manchester. This temperature seems too Carcel lamp.

high to be reached under any ordinary circumstances in It results, from my experiments, that the chances of a lamp, and I should consider them as ordinarily safe accident from the use of these oils may be referred oils. I submitted the remaining twenty samples to a almost exclusively to their greater or less proneness temperature of 150° F., and found that every one to form an explosive mixture with the air contained yielded an explosive mixture at that temperature; but in a partly filled bottle or lamp reservoir. I believe it this I consider beyond the limits of possible danger, and will be found that nearly all the accidents arising from I consider these twenty as very safe oils. the use of the new illuminating oils have been primarily Of the twenty samples which could not be made to caused by the ignition of the explosive mixture of com- explode at 120°, two were American rock oi's, and bustible vapour and air, either in the bottle in which eighteen were Young's paraffin oils; the whole of the stock of oil is kept, or in the reservoir of the lamp; Young's paraffin oils tested were safe oils. Out of the very few accidents happen while the lamp is burning, twelve samples which exploded at or below 120° all were they nearly all occur while pouring out the oil, or in American oils, seven of which were purchased in this lighting or trimming the lamp. The explosion may neighbourhood. break the vessel and scatter the oil about, and if it be | To recapitulate : Out of thirty-two samples I consider very inflammable in an ignited state.

I found twenty quite safe, three less safe but not really My examination was then chiefly directed to ascertain dangerous, and nine too dangerous to be used for whether any of the oils would form an explosive mixture domestic purposes; four only of the dangerous oils were with air at the medium temperature of 60° F.; this purchased in Manchester. Out of fourteen samples of temperature may represent the average temperature American oil, two were as safe as paraffin oil, three less of domestic rooms where the bottles of oil are kept. safe but not dangerous, and nine are to be looked upon To ascertain this point, about a quarter of an ounce of as dangerous the oil was put into a six-ounce stoppered bottle, the In addition to the explosive method of testing, I have stopper inserted, and the bottle shaken and moved about tried the liability of the various samples to burst into so as to facilitate the escape of vapour from the oil; in flame upon contact with a lighted body. I find this three or four minutes the stopper was taken out and a inflammability is in close, if not in exact relation with lighted match held to the mouth of the bottle: if there the explozibility ; but from various reasons I do not was a rush of pale blue light through the bottle, the oil consider it as good a method of testing. I find none of was said to give off an explosive vapour at the ordinary the samples of Young's paraffin oil to take fire at 1300; temperature, and to be highly dangerous ; only two out of fourteen samples of American oil eleven infame samples out of the thirty-two exploded at a temperature at this temperature, and three do not. When the oils of 60°, numbers one and three, from London and Liver. are scattered upon linen or woollen rags, at the natural pool respectively. But this temperature can only be temperature of the air, they burst into violent flame considered as the lowest limit of possible danger, the upon the most momentary contact with a lighted match actual limit of danger is the highest temperature to or candle; in this, the most dangerous property of these which, under all ordinary circumstances, the oil is likely oils, there is no considerable difference botween the best to be exposed, either in storing or while burning in the l and the worst samples of the American and parafiin oils.

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