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Analysis.--- 0.1333. grm. gave by combustion as before partial decomposition of the substance, which would be 0 4413 of carbonic acid, and oʻ1185 of water.

more liable to occur the higher the boiling point of the Density of vapour found.

3.7517

body. I do not, however, offer this as an explanation, Theory C16H10.

306665

but merely make the suggestion. The results show that this body has the formula C6H10, and that it is doubtless the third member of the benzole Remarks on Mr. Warren's Researches on the Volatile series. I. Although xylole--first discovered by Cahours

Hydrocarbons,by A. H. CHURCH. in the light oil separated from wood spirit-has had a much lower boiling-point assigned to it, I have retained In the CHEMICAL News of December 15, an account of the name for this body, since the results which I have Mr. C. M. Warren's careful experiments on the benzole obtained in the study of the light oil from wood-tar series is commenced. The way in which some of my indicate that when the corresponding body from this early results are criticised compels me to refer at once to

several of his statements. source is in an equal state of purity its boiling-point will agree with the above determinations. I may here Mr. Mansfield, but when this chemist's views are

Mr. Warren cannot confirm all the results of the late mention that I have obtained a body from wood-tar at believed to have been incorrect they are spoken of as about 140°, but nothing between that and 1.10°, although an expression of opinion in advance of anticipated special pains were taken with the intermediate fractions. That this body boiling at 140° is not identical with cumole results;" but when I am wrong, or supposed to be so, I from cuminic acid will be made apparent hereafter.

am severely handled. I am quite ready to admit that

my own opinions have in sereral respects been altered IV. Isocamole (Cymole of Mansfield). - Sp. gr. by further researches; while the admirable method of 0.8643a1 oo and 0.853 at 15°. The boiling-point was de- fractionating perfected by Mr. Warren has enabled him termined with the usual precautions. Before distillation to work far more satisfactorily than was possible at the commenced the temperature of the boiling liquid was time I tried my experiments on the subject-just eleven 1965° ; at the close (near dryness), 167o. With the

years ago. customary corrections for the average, viz., 166*75°, we

I regret that Mr. Warren has not made himself acobtain for the corrected boiling point 169.8o. Analysis.-0.1944 grm. gave by combustion, as before, series. Some of the results which he disputes I have

quainted with all my papers and notes on the benzole 0.6366 of carbonic acid and o'1896 of water.

already corrected, others I now interpret differently,

while one or two of his own discoveries I have antiCarbon

cipated.
90'00
:

89'31 Hydrogen

10'84

I. Benzole Series.- No chemist disputes the boil

ing points assigned to benzole, cumole, and cymole—the 100'15

bcnzole being obtained from coal naphtha and from Density of vapour found .

4'3019

benzoic acid, the cumole from cuminic acid, and the Theory

4'151

cy mole from oil of cumin. My own results published Hence it appears that the calculated density on the in 1855 were not new; they merely confirmed very formula C3H12 is 0'151 less than that found by experi- strongly the results of others :- Benzole, 80.8° C.; ment. The calculated density on the formula Chu pre- Cumole, 148.4° C. ; Cymole, 170°7° C. But I unintenviously assigned to this body, though without analysis tionally conveyed the impression that these particular or determination of vapour-density, is 4.645, which is boiling points with those of toluole and xylole had been 0*302 greater than that found by experiment.

taken with coal naphtha products in every case. The It will be observed that the difference between the identity of the hydrocarbons from various sources I had density found and that calculated on the formula C2H, accepted too implicitly second hand, but I did not regard is not only twice as large as the corresponding density it as a new discovery of my own, calculated on the formula C1g1112, but that the error is With regard to toluole and xylole the case is different. reversed; being with C2H, a deficiency, while with The xylole which I obtained with a constant boiling CisH , it is an excess. This circumstance goes strongly point of 126•2°, I expressly stated in my paper in the to show that the lower formula is the true one. I have Philosophical Magazine for June 1855 to have been but rarely met with an instance in which the density derived from wood spirit. This determination does not found was not greater than the theoretical density; and differ widely from that of Cahours-526°. My reasons I have usually observed that the excess of the experi- for believing a hydrocarbon of the same formula to cxist mental over the theoretical density is larger in propor- in coal naphtha are fully given in this latter paper. tion as the boiling point of the body is higher My determination of the boiling point of toluole does a fact which needs explanation. Wurtz observed a not differ widely from the results obtained by Glénard similar difference between the determined and calculated and Boudault, and has been since coufirmed by Max vapour densities of bodies of the formulæ CnHn and Dürre. These three determinations are, 103.7°, 1060 CnHn + 2, which he accounted for on the ground that and 104°. his preparations contained an admixture of bodies less II. Parabenzole Series. I am still convinced of volatile, the vapours of which would remain in the the existence of a series of hydrocarbons in coal, balloon and increase the density. But I do not accept naphtha isomeric but not identical with that to which this explanation for the substances here treated of, since benzole belongs. The mere non-discovery of parathey invariably distil without residue within a range of benzole in any specimen of coal naphtha cannot be taken one degree of temperature. I would rather rely on the as proving the non-existence of this body. The differ. supposition that the high temperature employed causes ences in boiling point, liquid density, solubility in oil of

In a note the author refers to the publications of Hugo Müller, vitriol, and specific refractive energy between benzole Béchamp; and Naquet, September, 1866. Müller's results, he says; and parabenzole I have already fully described. Wher: agree with his own. Béchamp erroneously regards it as a new hydro- the abstract of Mr. Warren's memoir is concluded I may carbon, not belonging to the benzole series. Naquet calls it a nero hydrocarbon, and gives the formula C18 II 12.

recur to this point.

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14

CHEMICAL NEWS,

Dec. 22, 1855.

"Dete} Supposed Nature of Air prior to the Discovery of Oxygen. 293

It is curious to notice that Mr. Warren, while disput- To conclude, I trust my experiments will enable me ing most of my results, actually confirms one of the to dispute the direct formation of saccharine matter by most important of them, though he does this unwittingly. the green parts of vegetables exposcil to the sun. He describes the hydrocarbon boiling at 140° as having the formula, CeHo, assigned to xylole. This is exactly on the Supposed Nature of Air prior to the Discovery what I have myself affirmed. The detection, &c., of this hydrocarbon is a discovery to which I lay claim. I of Oxygen, by GEORGE F. RODWELL, F.C.S. have already named this liquid para-xylole and assigned

(Continued from page 74 ) the formula C6H,, to it, and found it to boil between XIV. Rise of Pneumatic Chemistry:-We can 140 and 1419

scarcely be surprised that the air received but little

attention till a comparatively late period in the history On the Formation of Glucose by Leaves,

of the world, when we remember that there existed no by M. BOUSSINGAULT. *

means of ascertaining even its most salient properties.

Inquiries into the nature of an intangible and invisible The supposition tha: the production of glucose and its body, which exercises no apparent effect upon the congeners is principally effected by the aërial organs of matter around it, belong to a somewhat advanced stage plants is contradicted by the abundance of saccharine of experimental philosophy; they require the assistance matter in the sialks, the roots, and especially by the of a large amount of collateral knowledge, of a refined formation of the same matter during germination, manipulation, of a mind tutored in the mode of physical when the leaves are not yet formed. But the germina- thought, and used to the classification of diverse phetion only transforms starch into glucose, sugar, and nomena. The most obvious property of matter is its cellulose; it brings no combustible elcment; on the visibility, and the conception of it divested of that procontrary, the embryo, for its nourishment, consumes perty is no small effort to an ordinary mind: we all those pre-existent in the seed.

know the invariable wonderment produced at a popular By looking at the vegetable world in its entirety, one lecture when carbonic acid is poured upon a lighted is convinced that the leaf is the first resting place of taper, or when hydrochloric acid gas and ammoniacal the glucosides, which, more or less modified, are found gus are brought into contact. When we call to mind scattered in rarious parts of the organism ; that it is the the ideas which obtain among the wscientific in the leaf which claborates them, at the expense of the car- present day in regard to gaseous bodies, we cannot bonic acid and water. In maize, wheat, &c., the accumu wonder that so litt!c was formerly known of the air. lation of saccharine principles takes place in the stalk, The ancients, although they classed air among the up to the time of flowering, when all that has been four clements from which they conceived the world had forn.cd assists in the formation of the scrd. In beetroot been produced, had no definite idea of its naturr. Many this receptacle is the principal feshy root. But where philosophiers doubted irhether it were material, and the there is ncither stalk nor root, where is the saccharine great mass of the people scarcely recognised its existmatter formed by the leaf deposited ? In the leaf itself, ence. The fact adduced to prove its materiality (the which is then considerably extended. The most striking simplest and most obvious that could occur to the mind) example is presented by the American agave, the maquey, was that it could be felt when in motion-viz., as wind. the vine of the Mexicans, the culture of which extends Anaxagoras went a step further, and urged as an addifrom the time of Montezuma and further. The leaves tional proof (a) that a blown bladder resists compression, of the agave all grow from the neck of the root; they and (b) that an inverted drinking vessel when plunged attain 2 metres in length, 20 centimetres in breadth, and beneath the surface of water is found to remain per1 decimetre at the point of attachment. During from fectly dry inside, which would not be the case, he argues, fifteen to twenty years these leaves elaborate and accu- unless something material had prevented the ingress of mulate glucose, until the stalk which is to bear the the water. But these crude experiments merely prored flowers and fruits begins to form. Then the large, that the air is matter. coriaceous prickle-edged leaves, after having remained Then, again, the experiment of burning a candle in a 80 long inclined to the ground, raise themselves and closed vessel standing over water, could throw no light approach the conical bud, as if to cover and protect it. on the nature of the air, as it could not be rightly exThen there is a very apparent and gradual movement, plained in the then state of science. It may be conseeming to obey a will. The bud lengthens with sur-sidered the earliest experiment in pneumatic chemistry; prising rapidity, and a flower-stalk, 5 or 6 metres in it is mentioned by almost every Middle Age writer length, is soon formed. The work of reproducing the on alchemy and chemistry, but scarcely two give a seed is thus accomplished, and it is by preventing this similar explanation of the phenomena observed ; nor that the Indians procure an ample harvest of the sweet is this to be wondered at when we remember the sap, by fermenting which they prepare pulqué, their amount of chemical knowledge required for its explanafavourite intoxicating drink. One agave plant, in the tion. To explain it in its entirety it was necessary to environs of Cholula, yields in four or five months nearly know (a) that the air is composed of two gases ; (b) that i cubic metre of sweet liquid, after which it dies ex- they are insoluble in water ; (c) that during combustion hausted, as it would also die exhausted were the stalk one of them unites with the burning body; (dl) that a allowed to develope and bear flowers and fruit. An gas soluble in water is the result; (e) that the other gas agave yields in four months about 100 kilogrammes of cannot unite with the burning body; and (f) that in a glucose, prepared and preserved by its leaves for years.t known volume of air there are four volumes of the latter

There is no doubt as to the origin of this glucose; it gas to one of the former. No wonder the experiment proceeds from the carbonic acid and water decomposed puzzled the scientific mind for so inany centuries. No by the leares.

wonder it became a habit to fasten a pet theory upon it, Comptes Rendus, lxi., 664.

or to propound one specially for its explanation. Those See Boussingault "Sur le Pulque:” report made to the Imperial old philosophers who with difficulty spun outin paye Commission for Mexico.

or two about it, little thought how much was linked

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CHEMICAL , Supposed Nature of Air prior to the Discovery of Oxygen. {Cibe. ca

22. with the truc explanation of the experiment, how their qualites of the air.") he mentions that marcasite when ponderous and unwieldy theories, upon which so much exposed to the air becomes covered with a body of a thought had been expended, so little experiment, would vitriolic nature; he also considers that the efflorescence have disappeared utterly; how the face of science would on walls comes from the air, and suggests there is a be changed when a new race of thinkers, working something of a solar or astral nature, possibly “ a volaslowly and laboriously, were destined to elucidate each tile nitre,” dispersed throughout the air, and necessary phase of the experiment.

for the sustenance of life and flame. As an additional But although this experiment remained unexplained, reason for believing that there is some " hidden quality it proved to the inore observant the important fact that in the air, he mentions that he made a liquid of "subliflame requires air for its sustenance-a fact which, mate, copper, and spirit of salt," which was of a dirty red although by no meaus generally admitted, found sup- colour so long as it was kept in a closed phial, but when porters from the time of Hero of Alexandria. One of exposed to the air it changed to " a green exceedingly the first air-pump, experiments tried by Otto Von lovely.” Guericke was for the purpose of ascertaining whether I have mentioned above Boyle's supposition that there a candle would continue to burn in an exhausted re- is "a volatile nitre” in the air, and this leads us to the ceiver ; and Boyle, in his first pneumatic treatise (1660), consideration of that which I conceive fornis the basis of mentions several proofs that coinbustion cannot proceed pneumatic chemistry--the recognition of a connexion in a space void of air. In an essay on this subject,* between the air and nitre. We shall find as we proceed published by Boylo in 1672, we find hydrogen for the the vast importance of the experiments which were first time recognised as an inflammable body. Among made to determine the nature of that connexion. other experiments, he poured upon iron filings "a saline Let us first understand how such dissimilar bodies spirit, which by an uncommon way of preparation, came to be classed together. In the Norum Organum, was made exceeding sharp and piercing;" immediately Bacon urges the necessity of collecting together what “ fumes” were given off, which proved to be inflammable. he calls " a number of instances agreeing in one form." When allowed to burn within an air-pump receiver, the “ Inquisitio formarum,” he writes, “ sic procedit ; super Aame suddenly enlarged itself on exhausting, and then naturam datam primo facienda est comparentia ad intelwent out altogether. Boy le does not appear to have lectum omnium instantiarum notarum, quæ in eadem studied the properties of the new gas, but contents natura conveniunt, per materias licet dissimillimas.” himself with suggesting that it consists either of "the Following out this last clause to the very letter, Bacon volatile sulphur of Mars, or of metalline steams partici- takes the heat of the sun as the first " instance agreeing patiog of a sulphurous nature.”

in the form of heat," and classes with it the skins of Boyle also published in 1672 an essay entitled “ Fire animals and oil of vitriol, on the ground that the former and flame weighed in a balance," in which are detailed a (as he supposed) contained heat, and the latter burnt number of experiments made to determine the amount linen. On the same principle (and certainly with equal gained by certain metals during calcination. We have reason) some philosophers traced a relationship between previouslyt considered at some length John Rey's im- the air and nitre :-nitre, when thrown upon red-hot portant treatise on this subject, published forty-two coals, produces very intense ignition ; a blast of air years earlier. One of the first papers read before the directed upon red-hot coals produces the same effect, Royal Society (February 23, 1661) was “ On the weight the two instances obviously “in eadem natura conveniunt, of bodies increased in the fire.. The experiments were per materias licet dissimillimas.” This mode of procedmade by Lord Brouncker at the Tower of London, and ure may appear crude and likely to mislead, when we are given in detail in Sprat's " History of the Royal consider Bacon's classification of instances agreeing in Society;" but they are by no means concordant-so little the form of heat, but it must be remembered that he 80, indeed, that it was not considered as a proved fact gives negative instances which qualify the former, and that metals gain weight at all during calcination, for we enable the mind to decide whether certain instances find on March 20, 1661-" The amanuensis was ordered which appear at first sight to agree may really be to make the experiment of the calcination of antimony admitted as such. Moreover, the classification is only whether it increaseth or not; and to weigh it before and to be temporarily made, and then to be tested rigidly by after, in and out of the water."

experiment. The classification of the air with nitro (as Boyle found that an ounce of copper filings heated to also Newton's familiar classification of the diamond redness for two hours gained forty-nine grains, while an with combustible_bodies), belong to that class of inounce of tin gained one drachm during calcination. Tin stances called by Bacon " instantiæ conformes sive proand lead heated in hermetically sealed vessels, under- portionatæ," which he defines as "primi et infimi gradus went partial calcination, from which Boyle inferred that ad unionem naturæ,” leading the mind “ ad axiomata "glass is pervious to the ponderous parts of flame," and sublimia et nobilia."s that the gain of weight during calcination arises from Nitre has always been an important salt; it was “extinguished flame” assimilated by the calx. Boyle known in the East from very early times, and after the reduced lead from its calx, hence he considers a calx invention of gunpowder was largely imported into neither the “caput mortuum" nor the “ terra damnata" Europe. Gekopr, the earliest writer on chemistry (8th of the body calcined, as was generally believed, but rather century), mentions both nitre and nitric acid, and the as the body submitted to calcination plus something ab- former figures prominently in all alchemical and old chesorbed during calcination. It is curious that Boyle, who mical treatises. It was called salt petre from the fact of had worked upon the air with certainly more assiduity its being found adhering to rocks (netpos). Bacon than any of his contemporaries, should not have attri- attributes the force of gunpowder to the nitre wbich it buted the increase of weight of calces to the action of contains," which having in it a notable, crude, and the air upon the body calcined ; more especially as in a windy spirit, first by the heat of the fire suddenly dilatreatise published in 1674 (Suspicions about some hidden teth itself, and we know simple air being preternaturally * "On the Difficulty of Preserving Flame without Air."

Nov. Org., Lib. 2, Aph. 11. + CHEMICAL News, vol. x., p. 208.

Nov. Org., Lib. 2, Aph. 27.

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9

CHEMICAL NEWS,
Cubicle or was } Supposed Nature of Air prior to the Discovery of Oxygen.
Dec. 22, 1865.

295 attenuated by heat will make itself room, and break air which renders it the solvent of combustible bodies, and blow up that which resisteth it; and secondly, when "is like, if not the very same, with that which is fixed in the nitre hath dilated itself, it bloweth abroad the flame, saltpetre." as an inward bellows."|||

It has always been a matter of regret to us that Shortly after the establishment of the Royal Society, Hooke's theory of combustion has received so little attenMr. Henshaw (one of the first elected Fellows) read a tion at the hands of the scientific; it was only last year paper before the Society " On the History of Nitre,” that M. Chevreul (an authority on matters relating to the in which he says it is probabie " that the air is every- air), wrote in the Comptes Rendus, “ On doit a Stahl la where full of a volatile kind of nitre" generated in the premiere explication de la combustion."ft The theory of clouds, inasmuch as he has found it in dew and rain. Stahl, unsupported either by experiment or sound reaHe was informed, however, that no earth yields so soning, cannot be compared with the theory of Hooke, much as that of a churchyard, a fact which militated based upon experimental results, and supported by just somewhat against his theory. He speaks of nitre as and accurate reasoning: Hooke clearly showed the part "the darling of nature, the very basis and generation of which air plays in combustion ; Stahl adopted the phannutriment." In a history of nitre written by one tasy phlogiston. Then as to priority, Hooke's theory William Clark, and published in 1670, we find a section was perfected when Stahl was in his cradle, and was with the rather startling title " A Chemical Analysis of published when he was four years old. Hooke's theory Nitre;” nitre was heated in a retort with potters' was neglected simply because it was so little known, earth, when red vapours, smelling like aquafortis, and and this was owing to the manner in which it was known as “the flying dragon,” were copiously evolved; given to the world. Not published separately, it was an analysis, indeed, in the broadest sense of the word, not even designated a new theory of combustion; it but scarcely justifying the title of the chapter describing forms part of an article on "charcoal or burnt vegeit; for we must remember that a hundred years later tables" in the “Micrographia," a work in which we the term “chemical analysis ” could not justly be should scarcely look for a new theory of combustion, applied to any operation or series of operations in the inasmuch as it professes to detail" some physiological chemistry of the period. Clark considers that thunder, descriptions of ininute bodies made with magnifying lightning, and meteors are caused by nitre in the air; glasses.” Moreover, there is nothing to guide the Sennertus attributed thunder and lightning to the reader to the subject, and without reading the whole meeting of nitrous and sulphurous vapours—an idea book he would not be likely to meet with it, for it is evidently originating from the knowledge of the com- buried in a mass of irrelevant matter. It is, I conceive, position and properties of gunpowder. Clark attributes in the causes given above that we must seek for an exthe propulsive force of gunpowder to the sudden con- planation of the fact that one of the most original and version of the nitre it contains into air. He mentions complete theories, which has ever appeared in the history the fact that nitre was used by chemists for converting of science, was all but unknown in its own period, and some metals into calx, and he considers that metals has remained almost unnoticed down to the present day. become rusted when exposed to the air on account of the We have next to consider the important treatise “ De nitre which it contains. The latter part of Clark's sal-nitro et spiritu nitro-aëreo," of John Mayow; the history of nitre is devoted to the statement of some first of the five great works on pneumatic chemistry remarkably wild and useless speculations ; in one which were published before the discovery of oxygen. chapter the author proposes, and endeavours to support the supposition, "That the fiery rain of brimstone and fire on Sodom and Gomorrah was lightning; and that Chlorine Water. It has long been known that in nitre is expressed by the word fire."

chlorine water exposed to air and light hydrochloric acid Boyle, in a short essay entitled " A fundamental ex- is formed. Millon has lately shown that some hypoperiment with nitre," mentions that he prepared pure chlorous acid is also produced. More recently Barres will nitre by crystallisation, melted it in a crucible, and threw has proved the formation of some perchloric acid under red hot cinders into the molten mass until deflagration the same circumstances, which observation has been conceased ; he then added " spirit of saltpetre" to the firmed by Schmitt.-L'Institute, 1865, p. 231. residue, and set aside to crystallise; the crystals were

Preparation of Iodide of Potassium. - Fuchs found to resemble saltpetre in every respect. He also prepared nitre by mixing " common potashes and aqua- parts of distilled water, and adds thereto 75 parts of pure

places 100 parts of iodine in a porcelain dish with 260 fortis" and crystallising Although a certain relationship between the air and carbonate of potash and 30 parts of iron filings. The

. nitre was very generally admitted, philosophers were by mixture is well stirred together, and allowed to stand. no means agreed as to the form and character of that the application of heat. When the evolution of carbonic relationship. Some maintained that the effects produced acid has ceased, the mixture is evaporated to dryness by the air are due to its containing nitre,

others that the with continual stirring. It is better to allow the mixture effects produced by nitre are due to its containing air. to stand for some time in a lukewarm drying oren Thus, Hobbes and others considered that nitre consists until all the iron is peroxidised, and then evaporato of many orbs of salt filled with air ;” Gassendus, in to dryness. The dried mass is then placed in an iron

" common with a large number of philosophers, maintained

vessel and heated to a dull redness. The residue is that particles of nitre are diffused throughout the atmo. then extracted with the smallest quantity of distilled sphere; while Hooke, in his ingenious and philosophical theory of combustion,** affirms that the portion of the water; the solution, which has usually an alkaline re

action, is then saturated with hydriodic acid, and set || “Sylva Sylvarum. A Natural History in Ten Centuries."

aside to crystallise.:-Dingler's Polytech. Journal, Bd.

177, s. 251. Read August 14, 1651, and printed in Sprat's “History of the Royal Society."

# “Note historique sur les manieres diverses dont l'air a été envi. ** See the tenth of these papers, CHEMICAL News for February 17, sagé dans ses relations arec la composition des corps.” Comptes Rendus 1865.

for December 12, 1864.

Cont. 1, par. 30.

CHEMICAL News, 296 Observations on Some New Compounds of Pyroxyline.

. TECHNICAL CHEMISTRY.

which have lately been made the subject of experiment, with the view to their use in warfare. The author fur

ther states that the absorption of ammonia by the gunNote on the Preparation of Alizarine, by J. Wallace cotton is accompanied by an increase in weight, notwithYOUNG.

standing the elimination of a certain amount of oxygen

in the form of water. There are, he belieres, several JIAVING been lately engaged making some alizarine, and stages in the reaction, and he recognises particularly two after having tried various methods, I find that on a small bodies having the following formulæ :scale the following process gives good results, and is

Nitro-cellulo-triamide, C2H2,010(NO2)3,(NH,)3. readily performed.

Nitro cellulo-pentamide, C3,H2020(NO, S, (NH,)s. Garancine of good quality is extracted with alcohol ; the solution is distilled to recover excess of alcohol, and

It is not necessary for the present purpose to follow the residuum is carefully dried. A little of the extract the author through the remainder of a series of interestso prepared is placed in a small porcelain basin, and over ing bodies derived from the first of these by the action it is inverted a small beaker glass over the mouth of of lead and potassium salts, or of sulphuretted hydrogen ; which a piece of Altering-paper has been tied. A very but we cannot omit to refer to a statement which is emgerile heat is now applied to the basin, the extract soon

bodied in a more recent communication to the French 1980's, and alizarine sublimes, and is condensed on the Academy, and is printed in the Comptes Rendus of the bibulous paper. The success of the process depends 28th August last. M. Blondeau reinarks that he has almost entirely on the proper application and regulation succeeded in converting the ammoniated gun-cotton (the of tl.e hent; for, if it be too great, the sublimation is pentamide already referred to) into a kind of saline comconducted too hastily, and the product will invariably be bination by treatment with hydrochloric acid; and, contaminated or spoiled by an empyreumatic oil which furthermore, that the same product may be obtained by is formed. But if the temperature has been properly boiling, for half an hour, gun-cotton in a tolerably strong regulated the alizarine will be found in magnificent solution of sal ammoniac, then washing in a plentiful

The formula of ornoge red needles, often half an inch in length, adher- supply of water, and drying in the sun. ing to the filtering-paper. If the heat has been very low, the compound thus formed is stated to bethe crystals are often found resting immediately on the

C2, 112000(800),(NH2).(HCI). surlace of the extract.

The substance is said to be permanent, and to resist

decomposition at all temperatures not exceeding that of PHOTOGRAPHY.

boiling water ; it is equally explosive with, but gives off during combustion, certain products in addition to

those furnished by ordinary gun-cotton, particularly Observations on Some New Compounds of Pyroryline cyanogen and the vapours of chloride of ammonia. by John SPILLER, F.C.S.

Conceiving this substance to be well fitted for the pro

duction of a collodion which, by ihe addition of nitrate In the Comptes Rerdus of the Academy of Sciences, of silver, would become at once available for the collodioungler date May 30, 1864, appeared an interesting com-chloride process, I attempted its preparation in the hope munication from M. Blondeau, which was devoted to the that it might prove to be soluble in ether and alcohol

. description of some new ammoniated products of pyroxy- Failing, however, in the first attempt, I made repeated Jine upon the examination of which, at about the same experiments upon several different varieties of gun-cotton time, I happened also to be engaged in connexion with the exact quality of which the author omitted to spethe investigation of gun.cotton, undertaken by Mr. Abel. cify), following to the letter the instructions given, but The substances in question are formed whenever gun without being able in any instance to fix an appreciable cotton, or the soluble variety of pyroxyline, is exposed to quantity either of chlorine, or of the elements of amithe rapour of ammonia, and the chemical action facili- dogen. It is needless to observe that a mode of formatated by maintaining a slightly elevated degree of tem- tion founded upon the successive production of the amperature. The operation is best performed on a small moniated and of the chlorinated compounds would be too *cale, by treating some forty or fifty grains of explosive tedious to permit its use in the practical direction already cotton in a long-necked flask with aqueous ammonia indicated. (sp. gr. 880), added by successive portions of eight or ten Inasmuch as I could not perceive any alteration in the drops, and the flask fitted with a very loose cork, im- properties of the gun-cotton which had been boiled with mersed for an hour or two in a water bath kept at the solution of sal ammoniac, and failing in obtaining anatemperature of 100° to 120° Fahr... The colour of the lytical proof of the existence of chlorine and amidogen, gun-cotton speedily changes to a light yellow, which I proceeded next to compare the weight of the substances gradnally darkens to a russet brown, and its physical before and after treatment. In operating upon weighed aspect undergoes a modification, to the extent of becom- portions of the highly-explosive tri-nitro-cellulose, and ing a soft, friable mass, which still presents a fibrous likewise of the inferior nitro-compound usually employed appearance. By this treatment the explosive properties in the manufacture of collodion, I could not discover the romain almost, if not quite, unimpaired ; and it is worthy slightest increase, nor indeed any alteration, in weight of mention that the production of this substance in large as the result of such treatment. The samples were, of quantities is attended with risk, and that explosions have course, thoroughly washed in many changes of distilled occurred in the course of my experiments whenever I water (until nitrate of silver failed to show ang indication increased the amount of material operated upon, or en- of alkaline chloride yet remaining) and they were allowed deavoured to employ a somewhat higher temperature, in to dry by free exposure to air. According to M. order to expedite the reaction.

Blondeau's formulæ, which exhibit a constitution emM. Blondeau claims for his compound advantages on bracing a greater number of hydrogen and oxygen atoms the score of greater permanence and superior explosive than usually assigned by English chemists, the chloripower, when compared with the varieties of gun-cotton nated product should weigh at least one-third more than

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