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CHEMICAL News,
Sept. 29, 1865.

On the Estimation of Nitrites in the Presence of Nitrates.

147

SCIENTIFIC AND ANALYTICAL

Estimation by permanganic acid we shall dwell upon

at some length, for two reasons : first, because the process CHEMISTRY.

has been strongly recommended by authorities; and,

secondly, from the fact that, at first sight, this, of all On the Estimation of Nitrites in the Presence of the available oxidising substances, seems the most

Nitrates," by CHARLES R. C. TICHBORNE, F.C.s., plausible. Permanganic acid is instantly decomposed,

8c., &c., Chemisi to the Apothecaries' Hall of Ireland. even at 32° Fahr., by nitrous acid ; and, from the quickWhen I undertook tlie task of working out the last remedy the evils attendant upon this mode of estimation.

ness of the reaction, many plans have been devised to process for estimating nitrites I thought that the problem From the gaseous nature of nitrous acid, it is not would be one of extreme simplicity, and never calculated desirable to decompose the nitrites first by acids, preupon the numerous difficulties with which this project paratory to estimating them by a standard solution. was attended. I have carefully gone through the modes To avoid this source of error, Pean de Saint-Gilles has recommended by other experimenters (of which there recommended that the nitrite be decomposed by adding have not been many), and have also tried numerous loss of nitrous acid ;” but that this is not practically

very diluted sulphuric or nitric acid.

This prevents a original plans. From very few

of these have I succeeded correct is evident from the fact that iodised starch paper in getting accurate results. Of course, I now refer to becomes coloured on holding it in the orifice of the flask direct modes of estimating nitrites, more particularly in in which the nitrite is decomposed. Feldhaus says that the presence of nitrates. The difficulties are as follows: the salt must be diluted with 2000 parts of water, and the

ist. All the processes of estimating nitrites directly reaction commenced in a very slightly acidulated liquid; must be essentially processes of oxidation, as we are not when it is nearly completed, more acid may be added acquainted at present with any available precipitant.f if necessary, so as to ensure the marking of the exact Therefore arises the difficulty of estimating this com- point. Lang condemns the process. There can be no pound by oxidation in the presence of a powerful oxidiser doubt that by attention to the instructions given by -.e., nitric acid. We have no available precipitant for Feldhaus, and by working at a very low temperature, this latter acid either by which we could dispose of it. 2nd. Another prolific source of error in the estimation ments was to add the nitrite under examination to a

an approximation may be attained. One of my experi. of nitrites is one which seems to have been completely known excess of permanganate of potassium, and, as overlooked. It is the fact that at the slightest elevation nitric acid was present, to work off the excess by a of temperature nitrous anhydride, or nascent nitrous volumetric solution of oxalic acid. It is, however, im, acid, is partially decomposed and oxidised into nitric possible to determine the analysis, as, towards the end acid when in the presence of water.-that is, at the ex. l of the process, a reaction takes place between the perpense of that substance :

manganic acid added, the manganous oxide resulting in 3N,03+1,0=2HNO3 + 4NO.

a copious deposit of peroxide of manganeseExperiments proving this will be referred to further on.

2HMn,O4 + 3 Mn,0 - H N - 5Mn,Oz. The process recommended by Peligot, Lang, Jahresb. This reaction seems to take place even more readily 1862, p. 581, is not applicable to the examination of in the presence of nitric acid. nitrites containing nitrates. Also, the long digestion at

I attempted to decompose the nitrite by ignition with an elevated temperature (twelve hours at 869 to 104° oxide of copper, intending to wash the oxide, and, on Fahr.) is inadmissible. Lang says he got results only dissolving it in hydrochloric acid and chloride of sodium, 6 per cent. out, but I think he must have worked with to estimate the amount of cuprous oxide formed volupure nitrite of sodium. Feldhaus speaks against this metrically; but I found, even after prolonged ignition, process. In his experiments he seems to have got the the nitrite was not decomposed. results too high; the specimens of nitrite probably con. The most successful methods are those which I am tained nitrate. This process seems, in my hands, to give now about to describe. But I must premise that in all results too low, after the nitrite had been correctly processes of estimating nitrites by oxidation one thing accounted for. The urea process has been unanimously must be borne in mind that it is imperatively necessary condemned. Lang says it is bad, and Feldhaus also to set free the nitrous anhydride at a low temperature condemns it. As regards my own experiments, they in the presence of an excess of the oxidising material were so unpromising that I did not carry on my exami. for it must be remembered that nitrous anhydride or nation of this method to any extent, for to attempt to nitrous acid, when liberated in the presence of water, is estimate quantitatively free nitrous acid by a boiling decomposed at slightly elevated temperatures. solution is evidently radically wrong in principle. The following experiments will illustrate this fact:* Read at the meeting of the Pharmaceutical Conference.

if, at an ordinary temperature, a small portion of nitrite Nitrite of silver, the most insoluble salt, if we except the cobalt of sodium be dropped into diluted sulphuric acid in a test unless the water is at a very low temperature. Whether the cobalt will be filled with orange-coloured vapour, whilst a piece yellows (basic potassio-cobaltic nitrite ?), is readily soluble in water, tube, the following reaction will be observed : -The tube yellow is available for the estimation of nitrites is the subject of some experiments at present unfinished.

of iodised starch paper, held over the orifice, will be 1. A known quantity of dry peroxide of lead is added to a diluted slowly coloured. If, on the other hand, the test tube be solution of the nitrite to be analysed, and the solution mixed

with placed in a freezing mixture, previously to addition of peroxide dissolved corresponds to the nitrous acid-r at. peroxide the nitrite of sodium, no orange fumes will be observed,

but the colouration of the starch paper is instantaneous, (2Pb,0, + 2HNO, Pb,N,08 + Pb,H,O,). and very decided. In the first instance the nitrous acid

to , solution of nitrite acidulated, is added drop by drop until the solution oxide, the latter being evinced by the orange fumes of

was decomposel, as generated, into nitric acid and nitric produces a blue colouration with starch paste and iodide

of potassium pernitric oxide o.. its coming in contact with the atmo: CH,N,P+ HNO,=cO,+N+ HO,

sphere. From the aregoing it is evident that to estimate carbonic anhydrido and nitrogen being evolved.

a nitrite by an oxidis ng reagent, it is better that the VOL. XII. No. 304.-SIPTEMBER 29, 1865.

i at. nitrous acid

'148 Constitution of Acids belonging to the Acetic, Lactic, & Acrylic Series. { Cisepercas

, 1865. two be brought together at a temperature sufficiently much potash is added, a few drops of chloride of ammolow, that the oxidiser used may grapple with the nitrous nium and a boiling for a few minutes will rectify the acid previously to a reaction being set up between it and mistake. If the manipulation has been correctly per. the water. Experiments have been tried to find the formed, it will be indicated by the colour. The darkreaction of two of the principal oxidisers at a tempera- brown colour instantly disappears on boiling, the preciture of 32° Fahr. Permanganic acid was instantly de- pitate obtaining the bright green of chromic oxide, colourised. Chromic acid had no action at 32° Fahr., but whilst the solution becomes a bright yellow. on its being placed on one side, so as gradually to attain The chromic oxide is washed, but for accurate results the temperature of the room, decomposition took place the hydrated chromic oxide retains the chloride of potaswithout the evolution of any nitrous oxide.

sium too tenaciously to ignite and weigh directly. It is As stated in a former part of this paper, by a judicious better to re-dissolve the washed hydrated chromic oxide attention to a low temperature, and by a manipulation in diluted hydrochloric acid, and to re-precipitate with formed upon Feldhaus's plan, an analysis by permanga- ammonia in the usual manner. This gives the most Date of potassium may be performed, but still inferior exact results; but there are quicker methods. Thus, the in accuracy to the two processes I am now about to hydrated chromic oxide might be washed and converted describe.

into chromic acid by Chancel's method (by peroxide of The first process is based upon the reduction of lead) and estimated volumetrically. chromic acid to chromic oxide by nitrous acid. This Chromic oxide found x 1'354 = nitrite of sodium. is not so quick as with permanganic acid, but is per

...4Cr,0+ 3N203 = 31,08 + 2Cr Os. fected slowly at ordinary temperatures. Suppose we The second process is based upon the first, that both are analysing a specimen of commercial nitrite of nitrites and nitrates of the alkalies are converted into sodium, the mode of procedure I adopt is as follows:- chloride, upon ignition with chloride of ammonium. If the sample contains carbonate of sodium, a weighed Pure nitrite of sodium gives 84.78 per cent. of chloride quantity, say two grammes, is dissolved in a rather con- of sodium, whilst nitrate of sodium only gives 68-82. siderable quantity of water, and the carbonate estimated From these data, it is therefore easy to calculate the perby a standard solution of sulphuric acid, carefully avoid-centage, as anything under 84.78 indicates the presence ing an excess. To hit the exact point of saturation, of nitrate. I soak a piece of good litmus-paper in the solution It must be borne in mind that if the specimen contains after the addition of each quantity of acid from the carbonate, this would give the percentage of nitrite too burette, and on drying it the exact state of the solution high. As 100 parts of carbonate would give 110°37 parts is perceived. I may here remark that most of the of chloride of sodium after ignition, therefore it will be litmus-paper that is bought is not delicate enough for necessary to deduct an equivalent quantity of chloride this kind of work, as it generally contains some trace of of sodium from the results before calculating them. A alkali. A convenient indicator of this point of satura- weighed quantity of the nitrite is intimately mixed with tion in this case will be found in a solution of starch powdered chloride of ammonium, and introduced into a and iodide of potassium contained in a test-tube : one platinum crucible ; a gentle heat is applied, until the drop of the solution of nitrite added after each addition whole of the excess of sal ammoniac and other gaseous of acid will, when the carbonate is all decomposed, strike bodies are volatilised. The residue is dissolved in water, a blue shade on falling through the starch solution. After and the chloride of sodium estimated volumetrically with noting the amount of carbonate, the solution is in a fit a silver solution. position for the estimation of the nitrite; the remainder After a deduction for any carbonate of sodium present, may practically be noted as nitrate. Three grammes of the calculation may be made thus :pure bichromate of potassium for every two grammes of nitrite taken are dissolved with a little water in a flask

(NaCl- 68.82) + 100 fitted with a well-ground stopper; an excess of sulphuric

15-96 acid is then added, and the flask is placed in a vessel a being the percentage of nitrite of sodium. The chlocontaining a mixture of sulphate of sodium and hydro- ride of sodium left, minus the percentage of nitrate, chloric acid. The solution of the nitrite may be placed divided by the difference (15*96), will give the percentage also in the same freezing bath for a few minutes pre

of nitrite, or vice versa :viously, to being poured on the surface of the chromic

(84.78 – NaCl) + 100=1, acid without mixing; the stopper is then inserted,

15'96 the flask taken out of the freezing mixture, inverted, being in this case nitrate of sodium, nitrate of amand left to regain the ordinary temperature of the room; monium in solution is resolved on boiling into nitrogen in the course of half an hour or an hour the flask will and water. The applicability of this phenomenon to contain a mixture of chromic acid and chromic salt, the the estimation of nitrites will form the subject of a chromic oxide representing the nitrite in the sample. future communication. But here, again, in precipitating the chromic oxide a Many of the numerous experiments necessarily perprecaution is necessary. If there is any considerable formed in connexion with this paper were made by my excess of chromic acid left, which is generally the case, late assistant, Mr. Arthur Cranwill, to whom I take this when examining commercial samples, the ordinary opportunity of tendering my thanks. method of precipitating with ammonia would not do, as a brown precipitate of a peroxide of chromium (chromate of chromium ?) not decomposable by ammonia is on the Constitution of the Acids belonging to the Acetic,

decomposed, upon boiling, by a solution of potash into in conjunction with Mr. Duppa, the author had for chromic oxide and chromic acid. It is therefore neces- some time past been engaged in investigating synthetisary to nearly neutralise with potash, and finish off cally the constitution of the acids belonging to the with a few drops of ammonia, and boil until all trace of the latter substance is gone; but if accidentally to

Read before the British Association Birmingham meeting,

Section B.

CH,

C,H,

H

icou

с

Sept. 29, 1865.
, " }
The Reciprocal Action of Glycerine and Oxalic Acid.

149 acetic, lactic, and acrylic series. They had succeeded in that in future times the important researches performed building up the higher members of the acetic series from by Drs. Frankland and Duppa on the synthesis of acetic acid itself, by the substitution of hydrogen in that organic acids would be looked upon as the true foundaacid atom for atom, by the alcohol radicals, methyl, tion of what might be termed the anatomy of organic ethyl, &c. Numerous new members of the lactic series chemistry. These researches, of which an admirably had been in like manner constructed from oxalic acid lucid account had been laid before them by Dr. Frank. by the substitution of one atom of oxygen (0 = 16) by land, had produced a profound impression upon chetwo atoms of the alcohol radicals, whilst several mem- mists. He had lately travelled leisurely from Berlin to bers of the acrylic series had been produced from the Birmingham, visiting all the universities and schools lactic series by the abstraction of an atom of water from that lay on his way. Wherever he came the first questhe latter.

tion of his chemical friends was invariably, Have you These investigations had led to the following conclu- heard of the recent experiments of Frankland and sions :

Duppa ? As a remarkable feature of these experiments 1. The acids of all three series are constructed upon he must mention that there was scarcely a chemist the radical type. They are all double radicals, composed who had not, at one time or another of his scientific of a chlorous and a basylous constituent.

career, endeavoured to produce ethylacetic acid. The 2. The chlorous constituent is the same in all, and formation of this compound, which hitherto had been consists of an atom of methyl, in which two atoms of nothing more than a pleasant chemical dream, had at hydrogen are replaced by one of oxygen, and the remain- last been realised by a reaction which in beauty, siming atom by hydroxyl,

plicity, and generality could not be easily surpassed. c{01 It is this chlorous constituent which determines the The Reciprocal Action of Glycerine and Oxalic Acid ; basicity of these acids.

application to the Industrial Preparation of Concen. 3. The basylous constituent is variable, both homolo. trated and Monohydrated Formic Acid, by M. gously and heterologously. Its homologous variation

LORIN.* produces the different members of each series ; thus in FORMIC acid may be obtained by the splitting up of the acetic series we have :

oxalic acid under the influence of glycerine. The preH

paration by this reaction is regular, provided water be с

H
C H

added to the mixture so as to determine the separation H

H
H

of the dissolved formic acid, which is retained to about
0"
1он

{07 200°, and finally decomposes into water and carbonic OH

oxide. Procured in this way, the acid contains from 4 Acetic Acid. Propionic Acid. Butyric Acid Its heterologous variation, on the other hand, gives rise

to 5 per cent. of real formic acid. to different series of acids, of which the acetic, lactic,

I. Industrial Preparation of Formic Acid at and acrylic are examples. In the acetic series the basy; with dehydrated or commercial glycerine is heated in a

56 Centiemes.—The mixture of ordinary oxalic acid lous constituent is always an alcohol radical derived from methyl (except in formic acid, where it is hydro- retort. At 75o the reaction will commence, and will be gen). In the lactic series it is an alcohol radical derived in full activity at 90°. Simultaneously with the disenfrom methyl, in which one of the typical atoms of hs-gagement of carbonic acid, an aqueous liquid passes, drogen is replaced by hydroxyl (OH); whilst in the charged with formic acid. By the addition of a fresh acrylic series it is a similar alcohol radical, in which two quantity of oxalic acid, added some time after the cartomic member of the olefiant gas family. The relations richer in formic acid ; and by successive additions of of the typical atoms of hydrogen are replaced by a dia- bonic acid has ceased to be disengaged, the decomposition

immediately recommences; a liquid again passes still of these three series of acids to each other and to methyl oxalic acid, the richness in formic acid, of the liquid obmay therefore be thus simply expressed :Acetic Series. Lactic Series. Acrylic Series.

tained during this series of reactions, is always on the
н

increase, until it reaches a limit which is precisely that
H
H
H н
H

which crystallised oxalic acid should give. The equa-
H
H
OH

CH," tion-
C
C,
Cg
C

C,H,Os+HO = C,H,O + 4HO + C,D,
н
O"
0

0
H

shows that 126 grammes of oxalic acid furnish 82

он (H LOH OH

grammes of aqueous formic acid, which ought to contain, Methyl. Acetic Acid. Glycolic Acid. Acrylic Acid.

and, in fact, does contain, 56 per cent. of true formic After the paper of which the foregoing is an abstract acid. The existence of this limit is the result of the had been read, Dr. Hofmann, who temporarily occupied repeated and successive combination of the formic acid, the chair, made the following observations :

held back by the glycerine, with this polyatomic alcohol, He sincerely regretted that in the temporary absence that the quantity of water eliminated from the glycerine

-a combination rendered especially evident by the fact of their eloquent president it devolved upon him to address them on the memorable occasion of Dr. Frank is equivalent to the quantity of formic acid fixed in each land's communication. He congratulated the meeting

of the successive phases of the reaction. on the privilege they had enjoyed in listening to a from each kilogramme of oxalic acid, added in portions

In one series of experiments the aqueous formic acid resume of a series of inquiries, which in his opinion of 250 grammes, titrated 24, 44, 53 ; in a second series; would form an era in the history of organic chemistry. For many

years one of the leading aspirations of philo- | 17, 33, 41, 46, 50, and 51'5; the standard was raised sophers, working in the field of organic chemistry, had

more rapidly at the commencement of the operation. been the elucidation of the internal constitutions of the The excess of water, shown by these experiments to endless variety of carbon compounds, but he thought

Comptes Rendus, Ixi., 382.

(н

CHEMICAL NEWS, 150 On the Results of Agricultural Experiments in 1864. {

Sept. 29, 1865. exist in the first products, appears, then, to be the result acid under the influence of acetic and formic acids, of the formation of a compound of glycerine and formic may be utilised in the preparation of formic acid, 4. acid, the acid being regularly produced only after this Dehydrated oxalic acid, submitted to the moderate compound has ceased to be formed. The limit of satu. action of heat, furnished in one experiment a considerration has been found to correspond to 70 centiemes of able quantity of formic acid at 5. 5. From a theothe quantity of formic acid which would have been retical point of view the use of sulphuric acid as an necessary to saturate the glycerine, giving a mono- absorbent of aqueous vapour, is of some interest. I formine.

have operated on formic acid at 57's in the months This method of preparing formic acid of 56 per cent. of November and December, at the ordinary tempeis so continuous and regular that it is one of the easiest rature of the laboratory; by once in every three of chemical operations. No attention need be paid to the days weighing and taking the standard, always at the temperature, the disengagement of carbonic acid form- same hour, I was enabled carefully to follow the ing the initial and final phases of the operation. Start- phenomenon. Water is always absorbed more rapidly ing with 1 kilogramme of glycerine, and by successively than the acid, and the standard rises to 63; the relation adding 250 grammes of oxalic acid, we obtain, for each between the acid and water converges, and remains at kilogramme of acid added at one time, 650 grammes of about the limit 1'7. This relation, which differs a little formic acid at 56 per cent. It is moreover evident that from the = 1'704, seems to indicate, under these condiunder these conditions an equal weight of formic acid at tions, the existence of a hydrate of formic acid, corre25 per cent. costs no more than the oxalic acid which sponding to the formulahas served to produce it; for by the addition of water,

C,H,O3HO forming a litre of each quantity of formic acid collected Renewing the boiled sulphuric does not sensibly alter in the second series of experiments, I obtained the stan- this relation. 6. The easier preparation of formamide, dards 21, 26, 31, 33, 34. The glycerine being saturated, and especially that of pure carbonic oxide by formic and 1 kilogramme of oxalic acid furnished 1'5 kilog. of formic sulphuric acids, is another result of these researches. acid, at 25. The operation may be prolonged to any extent, and if after being used a long time it is found necessary to change the glycerine, it will be on account

TECHNICAL CHEMISTRY. of the impossibility of avoiding the almost imperceptible losses, and of the presence of impurities in the oxalic On the Results of Agricultural Experiments in 1864, acid. I have, however, used the same glycerine for

by Dr. STEVENSON MACADAM. several months, the operations continuing incessantly The experiments now referred to were undertaken at night and day.

the author's suggestion by agriculturists in Roxburgh11. Formic Acid at 35 Centiemes.-By making shire, and they form one of the first series of field experidehydrated oxalic acid act on saturated glycerine, I ments undertaken in a systematic manner in Scotland. obtain farmic acid at an average standard of 75. The Twelve different manurial mixtures were used in the heat, however, requires very careful management to trials, and formed a set of experiments, whilst ten avoid frothing. The decomposition of oxalic acid com- farmers made arrangements for carrying out the experimences at 50°.

ments in the field. The manurial mixtures employed III. Monobydrated and Crystallisable Formic consisted of Peruvian guano, phosphatic guano, phosphoAcid.- Monohydrated formic acid has hitherto been guano, bone ash, superphosphate, guano superphosphate, obtained by decomposing formiate of lead by sulphuretted sulphate of ammonia, and ground bones, taken singly or hydrogen, a long and difficult operation, which in un mingled together in definite proportions. The manures practised hands is rarely successful. I have, in the were analysed so as to be certain of their exact composifirst place, substituted formiate of copper, comparatively tion. In each set of experiments the various operations a very soluble salt, for formiate of lead, it being more were conducted on the same day with the plots of casily crystallised, dehydrated, and decomposed by sul- ground allotted to each manure. The soils on which phuretted hydrogen, and giving the theoretical quantity the experiments were made were in part of a heavy of formic acid. This is probably not the only case in nature, and in other part of a light character--the pro. which salt of copper would be preferable to salt of lead portion of each being equal. Each experiment was confor the preparation of organic acids. It occurred to me, ducted on a quarter of an acre, and the twelve experihowever, that the 25 per cent. of water might be elimi- ments consequently required three acres on cach farm, nated from the 75 per cent. acid by the use of anhydrous The crop was turnips, and the yield of produce was oxalic acid. On making this acid react at 70° on formic weighed on the field. The results obtained were acid, the temperature rises, the mixture becomes liquid various on the different farms, as the manures which when carefully heated, and when left to stand it crystal- gave the largest return on one farm did not yield the lises; by decanting and distilling to separate the dissolved largest crop on another, These variations are to be oxalic acid, formic acid, at a standard of about 100 is expected in all field experiments, and are due to the obtained, which, by a proper lowering of the temperature, special circumstances or conditions of each field where gives crystallisable formic acid.

the trials are made. Where only one set of experiments IV. Various Experiments. In the course of are conducter on a single farm, The local influences may these researches I have observed the following facts : materially affect the results ; but where, as in the pre-1. That of all the formiates, formiate of copper sent case, the field operations are conducted on ter alone when decomposed by heat, gives formic acid of farms, and the mean produce of the ten trials is obtained, only a certain degree of concentration--82. 2. What then the disturbing influences of one farm are counterever precautions I have taken, I have rarely obtained acted or practically neutralised by those of the other acids at 70 by the action of sulphuric acid on for- farms. Taking the mean produce from the ten trials, miates, and those always in relatively small quantities. calculated to the same money value for each of the With biformiate I have been not more successful. Ž. manures, the greatest return of crop was yielded by the The splitting up of ordinary or dehydrated oxalic dissolved phosphatic guano, followed closely by the

CHEMICAL NEWS,
Sept. 29, 1865.

Possibility of Manufacluring Neroli in British Colonies.

15!

Peruvian guano. Indeed, the difference in the produce essence of orange flowers called néroli? The result of obtained from the plots treated with these manures was my experiments in this direction was, that the two 50 slight-only 19 lbs. to the acre-that they may be essences are really identical, which conclusion was afterregarded as having yielded the same results. In refer- wards confirmed upon my return to Europe, by the ring to these experiments, it must be remembered that principal manufacturers of perfumes, whom I consulted the season of 1864 was exceptionally dry, though the on this subject, and who declared the essence of shaddrought was not so great in Scotland as it was in dock flowers prepared by me to be identical with firstEngland. The results obtained, however, are valuable rate quality of néroli. as representing the produce obtainable in a dry season, Another question of importance also arises :—Would and as a similar series of field experiments are being the manufacture of néroli in the tropical countries pay ? made this year in the same district, an opportunity will This can only be answered by practical experience. In be obtained for contrasting the results for both years. Java, where I made my experiments, the local circum- Abstract of Paper read at the British Association stances are such that the manufacture would certainly pay. Meeting.

But besides the neroli obtained by distillation of the flowers, there remains in the still after the distillation a

substance which deserves attention if ever my plan of On the Possibility of Manufacturing Néroli in the preparing néroli in the tropical colonies should be carried British Colonies,' by Dr. J. E. DE VRIJ.

out. If the residue in the still is thrown, yet boiling, When on my way to Java in the month of October, upon a cloth, the clear yellowish liquid which passes 1857, I passed through the South of France, my atten through the cloth deposits after a few days a large tion was fixed by the large number of orange trees cul. amount of yellow crystals. My experiments with these tirated in the neighbourhood of Cannes, Grasse, &c., for crystals have proved that they are identical with the the purpose of manufacturing neroli, which fragrant substance discovered in 1828 by Lebreton in unripe essence is exported from the southern parts of France, bitter oranges, and called by him " hesperidine." This and from Italy, to England and other northern countries. hesperidine, which I find very widely spread The high price of this essence induced me to inquire if genus Citrus, is the pure, bitter substance contained also it would not be possible to manufacture it in the colony in orange peels. As this hesperidine is a pure and quite where I was going to reside for some years.

innocent bitter substance, which can be obtained easily, A few months after my arrival in Java I fortunately and in tolerably large quantities, from shaddock flowers, had the opportunity of putting my idea into practice. it deserves, perhaps, attention as a substitute for hops. In Bandoug, the town where I lived, which is situate at an elevation of about 2300 feet above the level of the The Composition of Esparto Fibre, or Spanish Grass, sea, I was struck in the months of October and Novem- and its Employment in the Manufacture of Paper, ber by the fragrant smell of orange flowers, which per- by Dr. STEVENSON MACADAM. famed the whole neighbourhood. Upon inquiring the During the last three years large quantities of a grass cause I found there existed in that part many thousand have been obtained from Spain, and been employed in shaddock trees (Citrus decumana) whose flowers were this country in the manufacture of paper. It is collected the cause of the fragrance. This fact appeared very from lands which are, comparatively speaking, waste, curious to me, for although the fruit of the good kind of and, when delivered in Great Britain, costs about sl. ros. shaddock is one of the most delicious fruits in the to 61. per ton. The recent high price of rags necessarily tropics, this is only true when the tree is grown in very caused a demand for esparto fibre as a substitute for rags warm localities, as in the neighbourhood of Batavia, in the manufacture of paper ; and, should the demand situate almost at the level of the sea in about 69 South continue, other countries than Spain---such as Barbary, latitude.

which are known to yield the same grass--will no doubt In higher localities like that of Bandoug, where the contribute largely to the supply of the raw niaterial. average temperature is much lower than in Batavia, the The chemical composition of an average supply of fruit of the shaddock has only the size of an ordinary esparto fibre is as follows:orange, and is not eatable. As the many thousand

Moisture shaddock trees growing in the neighbourhood of Bandoug

Oil.

1923 were therefore almost useless, I thought it interesting to Albuminous compounds make some experiments on the preparation of the Ligneous fibre

56:28 essence of shaddock flowers. This seemed the more in.

Starch, gum, and sugar

22'37 teresting to me as I found the shaddock tree growing

Ash

5'04 at an elevation of about 4000 feet, producing an abundance of flowers. The fact that I once collected from one tree in my garden not less than 200 lbs. weight of In the manufacture of esparto fibre into paper,

tho flowers proves the abundance of flowers that may be material is first carefully examined and cleaned, obtained under happy circumstances.

and is then subjected to the action of a solution of I must mention that the wood of the tree is very hard, caustic soda. The proportion of soda employed is oneand acquires a beautiful yellow colour ; it may also prove eighth of the weight of the grass, being 14 lbs. of caustic to be of some value.

soda to the cwt. of fibre, or 2 cwt. to the top. The general After a great many distillations of several hundred size of boilers contains 12 cwt. of fibre, to which are weights of fresh flowers, the result was that the average added between 800 and 900 gallons of water, and it cut. quantity of essence yielded by 1000 lbs. weight of fresh or 154 lbs. of caustic soda. The boilers are either close flowers was i lb.

or open, and the boiling process is carried on for six or Having ascertained the amount of product, the follow- eight hours, during which time the soda dissolves away ing question arises :: Is the essence obtained by mc from the fibre the albuminous compounds, oil, resin, and from the petala of the shaddock trees identical with the silica ; whilst the starch and gum are also abstracted, Read before the British Association Birmingham moeting,

| Read before the British osociation.

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