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CHEMICAL NEWS, On the Manufacture of Alcohol from Coal.gas.

Jan. 3, 1863. moistened with the acid. When the acid no longer hydrogen depends evidently, in the first instance, on the absorbs smoke, the body impregnated with it may be nature of the coal distilled, and afterwards upon the washed for the purpose of extracting it; and this weak- manner in which it is distilled. If certain old and not ened acid gives alcohol on distillation. Before delivering very numerous analyses are to be relied upon, the prothe ordinary lighting gas for the purpose of being con- portion of bicarburetted hydrogen may be from 8 to 12 sumed, it may be treated by this method.”

per cent.; but under the conditions in which the manuThe specification of the patent is drawn up in such facture now takes place, we consider these figures as singular terms, that it is clear M. Castex's knowledge of much too high, and believe that 3 or 4 per cent. at the chemistry is not very extensive. As to making use of utmost would be much nearer the truth. We speak of lighting gas before its consumption for the production of the gas manufactured in retorts from the coals of alcohol, it is a perfect impossibility. The gas would no Belgium and the north of France. As to the gas manulonger give any light; and we do not recommend gas factured in coke-orens, we do not believe it has yet been companies to make any use of the idea broached by M. analysed. However this may be, the following is the Castex, for the consumers would soon rise in arms method which M. Cotelle appears to have adopted :against the application of such a process.

After having indicated in his patent many means The patent was taken out by M. Castex on the 8th of which he has probably tried, he condenses the gas, and December, 1854; and on the 15th of January, 1855-purifies it completely from its sulphuretted hydrogen that is to say, little more than a month afterwards-M. and ammonia, and finally passes it through concentrated Bertholet explained for the first time to the Académie sulphuric acid, which dehydrates it as much as possible. des Sciences his mode of producing alcohol synthetically. By means of a pump or exhauster, the gas is directed The nearness of these two dates may give rise to some to the base of an earthenware or glass column, filled reflections, from which we abstain, because we have not with plates or diaphragms, pierced with small holes, now to examine the question of the validity of the upon which the sulphuric acid at 66° descends, and which patent. For the scientific world, M. Bertholet is the first is, consequently, minutely divided. The column which author of the discovery; and the silence of M. Castex M. Cotelle used when we witnessed the operation, had is a mode of acquiescence which has some importance. only fourteen plates or diaphragms, and a single passage

Let us now speak of the experiments of our celebrated of the acid did not suffice to absorb all the bicarburetted chemist. It is not with smoke that M. Bertholet pro- hydrogen of the gas, and, at the same time, to saturate duced alcohol, but from the bicarburetted hydrogen, or all the acid. According to the inventor, a cascade of six olefiant gas. He introduced into a flask twenty-six litres plates would be required to accomplish these two objects of this gas, a quantity of concentrated sulphuric acid, at one operation—the absorption of all the bicarburetted and three kilogrammes of mercury—the use of which in hydrogen, and the saturation of the sulphuric acid. the operation is, we apprehend, for the purpose of Let us suppose this desideratum obtained. The carminutely dividing the particles. He then agitated the buretted hydrogen and the propylene are absorbed in whole together for a considerable length of time. After the column, and there remains from 96 to 97 per cent. about 53,000 agitations, it was found that the whole of of light carburetted hydrogen, hydrogen, and oxide of the gas had been absorbed by the acid, and that a real carbon, without value for the purpose of giving light, combination was formed, producing an acid, to which but capable of being used for the purpose of heating, the name of sulpho-vinic or sulpho-ethylic was given. It is principally with the object of so using them that

In treating this acid with water, a new reaction was the pump or exhauster is required, so that the gas may produced. The bicarburetted hydrogen set at liberty be drawn off or propelled in any direction without combined in its nascent state with water, forming increasing the pressure upon the retorts. alcohol, leaving the sulphuric acid combined with the The sulpho-vinic, or sulpho-ethylic acid, which M. addition of a certain quantity of water-that is to say, Cotelle calls his vinasse, is treated with five times its diluted-and, according to the formula of equivalents, volume of water, and the mixture is then submitted to we have C.H. + 2 HO = C.H.02. The alcohol produced the action of a current of steam, which carries with it is expelled from the liquid by heat.

the alcohol produced. These vapours are condensed, and Up to the present time, M. Bertholet has made no the alcoholic liquor is obtained. This is distilled on a attempt practically to utilise this curious experiment. little lime to saturate the sulphuric acid which has been Possibly, he was frightened by the difficulty which carried with it, and the products of this distillation are attended the absorption of carburetted hydrogen by even rectified, and alcohol of 90° is obtained. the most concentrated sulphuric acid; and he has con- The sulphuric acid which has been diluted by the tented himself with sending to the International Ex- operation so as to reduce it to 20° or 25° of strength, hibition a litre of alcohol thus produced from its must be concentrated to 66° if required to be used over elements, which may be seen in the glass case of M. again, or some other use must be found for it in its Ménier, No. 204, Class II. of the French Department. diluted state. This use of it, advantageously if it is

What M. Bertholet has not attempted, M. Cotelle, of possible, involves the establishment of another factory $t. Quentin, has since realised. Like M. Castex, he has on a large scale, even for a distiller producing 30 hechad the idea of employing coal-gas for the production tolitres (660 gallons) per day; for the quantity of sul. of alcohol, but not before using it for the purpose of phuric acid at 66° to be employed is considerable. It giving light. Coal-gas, well purified, contains light car. amounts to about 1500 kilogrammes (30 cwt.) of acid buretted hydrogen, bicarburetted hydrogen, carbonic for each hectolitre (22 gallons) of alcohol produced, or oxide, hydrogen, and certain carburets, more or less well 45,000 gallons (45 tons) of acid for 30 hectolitres (660 determined —such, for example, as a trace of propylene, gallons) of alcohol. Should it be desired to concentrate aniline, and even, perhaps, of acetylene. of these the diluted acid, apparatus must be provided such as is various gases or vapours, the bicarburetted hydrogen is, used in the sulphuric acid factories. This, truly, is not with propylene, the sole useful element for the purpose a manufacturing impossibility; but what will be the proposed. Unfortunately, it exists only in very small cost of concentrating for 1500 kilogrammes of acidproportions. The richness of coal-gas in bicarburetted that is to say, for one hectolitre of alcohol ?

CHEMICA, NESTA On the Preparation of Artificial Mineral Waters.
Jan. 3, 1863.

3 This expense of concentration appears to us, in the it disengaged acetylene, and, thrown on a heated metallic actual state of chemical industry, to be a grave difficulty plate, a louder explosion resulted than with pure acetyin the way of the success of the new process, even when lide, and without deposit of carbon. This difference the complete absorption of the bicarburetted hydrogen will be readily understood, for the acetylide formed is easily effected, as well as the simultaneous saturation during my experiments, finding itself in presence of of the sulphuric acid ; and we are quite sure that it would excess of oxide of copper, the carbon and hydrogen of the be necessary to make a new estimate of the cost price acetylide were entirely destroyed. which the journals of St. Quentin, with laudable zeal, It is evident that copper, in presence of air and acety. but with too much precipitation, had fixed at 25 francs lene, is spontaneously transformed into acetylide of per hectolitre of alcohol of 90°. Any serious estimate copper containing excess of oxide. As lighting gas of the cost price must have been premature, as M. contains acetylene, a little air, and perhaps even some Cotelle was not provided with suitable apparatus to ammoniacal rapours, it is obvious that acetýlide of copper determine it.

may be formed in tubes which have served to conduct Twenty-five francs per hectolitre for alcohol of good lighting gas.- Comptes Rendus. taste (it is said to be exempt from all empyreumatic flavour), the selling price of which was 70 francs! Here was enough to set all the speculators in a ferment, and

PHARMACY, TOXICOLOGY, &c. to cause serious reflections to all distillers, and even the manufacturers of sugar and agriculturists. Purchasers On the Preparation of Artificial Mineral Waters.* presented themselves from all quarters, anxious to treat

(Concluded from page 295.)" with M. Cotelle for his patents, French as well as

Sulphurous Waters. foreign, on condition, be it well understood, that he satis

In the preparation of artificial sulphurous waters for fied them on the subject of cost price. The French patent drinking purposes, it is recommended to employ the was sold, it is said, for 20,000 francs, and the English one crystallised monosulphide of sodium, and it is stated for 480,000 francs. A company was formed at St. Quentin, that it is unnecessary and objectionable to pass free with a capital of 16,000 francs, which was subscribed in sulphuretted hydrogen into the solution. The atmo. an hour, for the purpose of constructing a real manufac-spheric air dissolved in the water is always sufficient to tory, and solving the problem on a manufacturing scale. effect the decomposition of some of the sulphide of Since then-that is to say, about two months ago--the sodium, and set free some sulphuretted hydrogen. We enthusiasm has abated, the matter has been examined extract the formula for Baréges water, to show the dose with more sang froid, and it is generally admitted that of sulphide of sodium prescribed : the cost price can only be ascertained as the result of a manufacture on a practical scale, and not by approxi

Baréges Water. mative experiments in a laboratory,

Sulphide of sodium, crystallised · 0'2co grammes.

Silicate of soda (To bo continued.)

Chloride of sodium

0'072 Distilled water.

1 litre. On the Formation of Acetylide of Copper in Copper In the preparation of sulphur baths, the authors

Tubes for conveying Lighting Gas, by M. CROVA. recommend a polysulphide of a definite composition to It is well known, that copper tubes, long used to con- be used, instead of the variable compound obtained by duct lighting gas, have sometimes, during the cleansing fusion ; and, as no particular advantage is known to be of the interior, occasioned very dangerous and sudden derived from the use of a salt of potassium, the sulphide explosions, occasionally proving fatal to the workmen. of sodium is prescribed as being the cheaper compound. In one of the scientific reviews, an accident of this kind The following is the preparation recommended for the is recorded as happening at Philadelphia.

next edition of the Codex : Acetylide of copper having the property of detonating Monosulphide of sodium, crystallised . 125 grammes. by an elevation of the temperature or by a blow, and

Flowers of sulphur the presence of acetylene in lighting gas having been

Distilled water recently proved by M. Berthelot, I have tried to ascer- Dissolve the sulphide of sodium in the water, then add tain whether acetylene, in presence of air, could combine the sulphur, and heat gently until the latter is dissolved. with copper, and so form acetylide of copper.

The solution obtained in this way will contain exactly By passing a mixture of air and moist acetylene 100 grammes of penta-sulphide of sodium, which is suffithrough a glass tube containing bright copper turnings, cient for a bath. this metal tarnishes rapidly, assumes iridescent colours, Products derived from Mineral IVaters. and finally becomes black; but as this alteration takes The substances derived from mineral waters which place only on the surface of the metal, it is very limited.

are employed in medicine may be arranged in two By using copper reduced by hydrogen, I extended classes. The first comprises the deposits formed sponthe surface of the metal. A small quantity of metal taneously, either on the soil in the neighbourhood of the was placed in two flasks containing a mixture of equal springs, or in wells or basins in which the water is convolumes of air and acetylene, and also in one of the fined. In the second class may be placed the saline flasks a drop of ammonia. The two flasks, well stop products obtained by the evaporation of the waters. pered, their necks plunged in water, were left to them. * Chemists have always recognised the fact, that the selves for two days. They were then carefully opened, extraction of all the salts in a mineral water, and with and the water entering them absorbed nearly half the the molecular arrangement assigned to them by Nature, gaseous yolume. The absorption scemed to be somewhat is an operation beyond our art. By submitting a natural greater in the flask containing a little ammoniacal water to a moderate temperature, it loses the character vapour. The copper turned black. After washing and drying, I found that it contained a notable quantity of

* Abridged from a Report to the Société de Pharmacie of Paris, by

MM. Chatin, Poggiale, and Lefort. Journal de l'harmacie el de Chimie, acetylide of copper; for, hcated with hydrochloric acid, 1 t. xli. p. 376-410

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CHEMICAL News, 4 Court of Queen's Bench.

Jan. 3, 1863. of a natural water, and can only be considered as a solu- ) known in chemistry for about thirty years. Between 1845 tion of artificial salts; for the mode of combination of and 1850 I constantly worked on aniline to see what reacids and bases has been completely changed by the sults could be produced from it. In 1859, or early in 1860, evaporation of the liquid and the volatilisation of the I discovered the peculiar properties of aniline in combinagas. The salts, therefore, even when obtained from the tion with arsenic acid. They produced a very brilliant

magenta.' I patented the natural source, as at Vichy, can only be looked on as arti- dye, which is now called

discovery, and afterwards found out that Dr. Medlock had ficial products.” Bicarbonate of soda, prepared with care, is, conse

previously patented the same thing. Our firm afterwards

purchased Dr. Medlock's patent. Before the time I quently, to be preferred to Vichy salts for the prepara- hare mentioned no such colour had been produced by tion of Vichy pastilles or soda lozenges, and the authors aniline and arsenic acid. I was then, and am now, satisrecommend the following formula :

fied of the novelty of the invention. (A copy of Medlock's Bicarbonate of soda

36 grammes. specification was here put in, and read to the Court). By Powdered sugar

the process described magenta colour is produced, which, Gum Tragacanth

by treatment with different preparations, gives different Water

shades of colour. In my judgment this process was new. The above mass is flavoured by the following mixture of The colour is largely used, and has become a very valuable

article *. I know Heilman's patent. (See CHEMICAL News, essences :

vol. vi., p. 302). My attention has been drawn to it since English oil of peppermint

0·20 grammes.

this action was brought. (Specification put in). That Oil of orange-flower

patent professes to treat aniline with various salts and lemon

0:30

substances,—200 at least, but it may include 500. I have

tried several of the things mentioned ; an immense aniseed

Co25

обо Tincture of vanilla

number of them produce no colour whatever. A person

would have had to work, perhaps, six months to find out The essential oils are to be dissolved in three times their what it was produced the colour according to that speciweight of alcohol, and mixed with the lozenge paste fication. It was only a provisional specification ; and no while it remains very soft. It is stated, that the soda was aware of it except the Clerk of the Patents. pastilles are much better preserved in card-boxes than Arsenic acid is a combination of metallic arsenic with five in closely-stopped bottles. In these latter they are said equivalents of oxygen, and containing water of constituto become damp, and acquire a disagreeable alkaline tion, not water mechanically mixed with or adhering to it. taste.

The water is in chemical combination with it. Anhydrous arsenic acid is arsenic acid absolutely free from water,

Lord Chief Justice Cockburn: You start with saying COURT OF QUEEN'S BENCH.

that arsenic acid is a combination of the metal with DECEMBER 10, 1862.

oxygen :-Witness : And water,

Lord Chief Justice Cockburn: Well, suppose you want

to distinguish dry arsenic acid from the arsenic acid you Simpson and Others v. Wilson and Another.

have been speaking of, what would you call it :- Witness : This was an action, directed by the Court of Chancery, to I should call that dry arsenic acid--that which I have just try the validity of Medlock's patent for improvements in mentioned: the combination of arsenic, oxygen, and water the preparation of red and purple dyes. (See CHEMICAL is dry. News, vol. vi. page 302.) The declaration, after stating Lord Chief Justice Cockburn: Then there is no difference that Medlock's patent is now the property of the plaintiffs, between arsenic acid and dry arsenic acid ?-Witness: No. alleged that the defendants had infringed the said patent, Mr. Boyill: The distinction is between anhydrous and by manufacturing and selling a red dye of the colour, dry, commonly known as magenta or roseine, made according Lord Chief Justice Cockburn : You do not mean by dry to the process described in the specification of the said that from which the water, which has been mecbanically patent. To which the defendants pleaded

united with it, is removed - Witness : I should call this 1. Not guilty.

dry, my lord (holding up a bottle of arsenic acid). 2. That Medlock was not the first and true inventor.

Mr. Bovill: Although it contains water ?-Witness : 3. That the manufacture was not new.

Yes; water as part of i:s chemical constitution. Anhy4. That the manufacture was not new, nor an improve- drous acid is that from which all water has been driven ment in any way useful or beneficial to the publie. off. The term “anhydrous" implies, free from water. In 5. That the patentee did not, within six calendar

our process we use what is called dry arsenic acid, which months after the date of the patent, file an instrument in means arsenic acid that contains a certain proportion of writing, particularly describing the nature of the inven- water in its constitution. Arsenic acid is produced by tion, and the manner in which it was, or might be, per- dissolving arsenious acid--the white arsenic of commerce formed.

-in nitric acid, and boiling the solution down until it Counsel for the plaintiffs, Sir Fitzroy Kelly, Mr. Grove, solidifies into a dry powder. In boiling down, a large Q.C., Mr. Borill, Q.C., Mr. Drewry, and Mr. J. A. quantity of water is driven off, and that brings it to the Russell. For the defendants, Mr. Hindmarsh, Q.C., and state of what we call dry arsenic acid, leaving, still, a Mr. Day.

certain portion of water. In the absence of Sir F. Kelly the case was briefly Lord Chief Justice Cockburn: Let me see that I disopened by Mr. Grove, after which the following evidence tinctly understand you. You say that the driving off the was called for the plaintiffs :Mr. G. C. Nicholson (examined by Mr. Bovill) : I am acid :-Witness : Yes, my lord.

quantity of water brings the acid to the state of dry arsenic one of the plaintiffs, and a member of the firm of Simp- Mr. Bovill: Which still contains a certain portion of son, Maule, and Nicholson, manufacturing chemists, of water which is not driven off ?-Witness : Yes, exactly. the Atlas Works, Newington. I have given much atten- Lord Chief Justice Cockburn: That is, it retains it in tion to the study of chemistry and the preparation of dyes. chemical combination ?-Witness : Yes. I conduct the chemical department of our business, and By Mr. Bovill : The portion of water driven off in boiling am well acquainted with the body called “aniline." It is

It is necessary for us to remark here that our report is confined an oily basic liquid produced from coal tar, and has been to the chemical evidenco.

}

Court of Queen's Bench. Jan. 3, 1863.

5 was, in mechanical combination, water of solution. We anhydrous, yet, for all the purposes of commerce and of cannot produce any effect on aniline by arsenic acid until this manufacture, is dry. water is driven off down to the point at which it becomes Mr. Bovill : Then, as I understand it now, you produce dry arsenic acid. Arsenious acid will not do it; but if the dye by taking the dry arsenic acid and mixing it with we take arsenious and nitric acids, and drive off the water, aniline -Witness: Yes. we produce dry arsenic acid, which will act on aniline. Mr. Bovill : You may equally make the dye by pro

By Lord Chief Justice Cockburn : Arsenious acid is con- curing arsenious acid, aniline, and nitric acid, mixing verted into arsenic acid by the action of nitric acid. The them together, and then driving off the water; and the nitric acid parts with a portion of its oxygen, which is reason why you produce it is, the water being driven off, superadded to the arsenious acid, and then we get arsenic you leave dry arsenic acid-not dry to the sense of touch, acid. The water driven off in boiling is not that which but chemically dry arsenic acid ?-Witness : Yes. enters into chemical combination-it is water of solution Mr. Bovill: And what is it produces the colour? Is it or in mixture.

the action of dry arsenic acid on the aniline :-Witness : Lord Chief Justice Cockburn : Suppose you did not Yes, it dehydrogenates the aniline. There is no difference drive the water off at all, but having got arsenic acid you between the processes, whether you take dry arsenic acid used it without going on boiling :-Witness: We should and mix it with aniline, or take the two things from which not get colour until we boiled it down for the purpose of arsenic acid is made. getting all the mechanical water, if I may so speak, out Lord Chief Justice Cockburn : In fact, in the one instance of it.

you start with dry arsenic acid already prepared, and in the Lord Chief Justice Cockburn : You must get it into a other you prepare it in the first stage of the operation. dry state --Witness : We must get it into a dry state prior By Mr. Bovill : The addition of a metallic oxide in a to the dye being formed.

mixture of the three would produce no effect as regards Lord Chief Justice Cockburn : Then you must get it the colour. There was no process before by which the it into an anhydrous state, must you not?---Witness: No, colour could be produced so beautiful and so cheap. Many certainly not.

thousand gallons of it are sold. Lord Chief Justice Cockburn : Not if you drive the Cross-examined by Mr. Hindmarsh: I am well acquainted water off?-Witness: The mechanical water, I am speaking with the various modes of producing this dye. One of the of.

colours produced is old, the other new. The purple was Lord Chief Justice Cockburn : However, you say you new at the date of this patent. The red had formerly been get no results until you come to the dry arsenic acid ? - prepared. The processes in use before consisted, to the Witness : Until we boil off the water of solution from best of my belief, in the application of two oxidising agents, dry arsenic acid.

nitrate of mercury and nitric acid. I have read the various By Mr. Bovill : No water but that in the nitric acid is patents relating to the production of the colour. They are used in making arsenic acid ; and all of this is driven off very numerous. I believe only two relate to the use of except what remains in chemical combination.

oxides. Bichromate of tin will not produce the colour. Mr. Bovill: Now then, in using the dry arsenic acid I have read a specification of Brooman's, in which he with aniline, after you have produced it, do you use the proposes to use a good many anhydrous salts. I believe dry arsenic acid for the purpose of producing colour :- I have read another in which he proposes to use anhy. Witness : We do not mix the dry arsenic acid with aniline. drous bichroinate of tin. Bichloride of mercury is not ári

Mr. Bovill: Just describe the process.-Witness: Having oxidising agent; it contains no oxygen. It may, perhaps, got our dry arsenic, we mix it with aniline, and heat the be a dehydrogenating agent. Iodine and five hundred other mixture. The application of heat produces the melted things have been so described. Arsenic acid was used in mass which contains the magenta dye, and which, when cotton print works before the date of this patent. I have dissolved in water and boiled down, produces the pure never seen it used, but I know it is used as a discharge in solid magenta. I should say that any nitric acid in the place of tartaric acid. The mode of making arsenic acid mixture would have no effect in producing the dye. I have described is mentioned in books on chemistry. 1

Lord Chief Justice Cockburn: What I understood you do not remember that the result is, in Graham's book, to say just now was this:-If you take arsenious acid and described as a perfectly anhydrous acid. nitric acid, and combine those with heat, you will get, as Mr. Hindmarsh: So far as you know, is there any book you say, arsenic acid, the nitric acid parting with a portion which describes the making of arsenic acid, which would of its oxygen, and increasing the strength of arsenious acid not produce the material positively dry or anhydrous ? until it brings it up to the state of arsenic acid. Then, as Witness: I do not know. I understand, before that combination will act on aniline Sir F. Kelly: That is rather a comprehensive question. to produce the dye, you must drive off the superfluous If we are to have the book put in, in which the manufacwater of solution, so as to bring the arsenic acid to the ture has been described, I apprehend the passages should state of dry arsenic acid ?-Witness: Exactly so, my lord. be read in order that we may understand the question;

By Mr. Bovill : If any person were to take arsenious but to ask the contents of every chemical book is too comacid, nitric acid, and aniline, and put them all together, I prehensive.--Witness: One book will contradict another. do not think any effect at all would be produced ; but, Lord Chief Justice Cockburn: Do you know of any when the three are subjected to heat until the water is process given in scientific works on chemistry in which driven off, the dye would be produced, if the operation nitric acid is used where the result would not be anhy: were conducted properly: if done improperly, it would drous !--Witness: If I were to perform the operation I blow your head off. The dye is produced, because in that should produce a dry arsenic acid. process the arsenious acid is converted into dry arsenic acid. Lord Chief Justice Cockburn : The question put by Mr. Mr. Bovill : Does your lordship follow it?

Hindmarsh relates not to dry but anhydrous acid. --Witness: Lord Chief Justice Cockburn : I do not, indeed. I have Let me read the passage : This acid is obtained by heating attended to it, but I have not been able to understand it. powdered arsenious acid in a basin with an equal quantity

Sir F. Kelly: There are three states of this arsenic acid ; of water, and adding to the mixture at the boiling point the one with the water belonging to it in the operation, nitric acid in small quantities so long as ruddy fumes which, when the water is driven off, becomes dry arsenic escape. An addition of hydrochloric acid is generally acid. Then, to make anhydrous, the small quantity of made to increase the solubility of the arsenious acid, but water which is in chemical combination must be got rid of it is not absolutely necessary. The solution of arsenic acid also; but for the purpose of this operation it is quite is then evaporated to dryness to expel the remaining nitric enough if you make it dry, which is not, strictly speaking, I and hydrochloric acids, but the dry mass is not heated

6

CHEMICAL NEWS, Court of Queen's Bench.

{ Jan. 3, 1863. above the melting point of lead, otherwise oxygen gas is / far as I recollect, I did not mention solution of arsenic emitted, and arsenious acid reproduced.” I say that, if | acid. In substance, unquestionably, I mentioned solution I were to perform the experiment according to these in- of arsenic acid, because I found that answer my purpose structions, I should get, according to the temperature I at the time. used, dry arsenic acid or the anhydrous acid.

Mr. Hindmarsh: Is not this what you described : “ In Mr. Hindmarsh: You stopped short ; go on with the carrying out this invention, I take a strong solution of passage.-Witness reading : "Arsenic acid thus obtained arsenic acid, to which I add aniline, toluidine, cumidine, is milk-white and contains no water.” That is not abso- or mixture of the same. I then heat the mixture in a still, lutely correct. It may be white, and contain water or no or other convenient vessel, until the colour is sufficiently water. When nitric acid and arsenious acid are mixed developed."-Witness : That is my provisional specificatogether there may be no nitric acid or arsenious acid tion. I have made the colour with dry arsenic acid. I present: they may destroy each other. Nitrous and cannot recollect whether I added water to the experiment. arsenic acids are formed. It is not necessary to apply Dry arsenic acid is not mentioned in my specification. a high degree of heat to drive off the nitrous acid. There Some months after we purchased Medlock's patent, I may be something wrong in the description given by Mr. became aware of Delaire and Girard's process. They proGraham. I know “Fownes’ Chemistry." I do not know pose to use definite quantities of arsenic acid, aniline, and the process given for making arsenic acid. (Book handed water, and apply heat to the mixture (see CHEMICAL up and description read.) “Powdered arsenious acid is News, vol. vi., p: 314), for the purpose of converting dissolved in hot hydrochloric acid, and oxidised by the aniline into a red vlye. I hare tried the process experiaddition of nitric acid, the latter being added as long as mentally with certain definite quantities of aniline, arsenic red vapours are produced : the whole is then cautiously acid, and water. When the whole of the water is driven evaporated to complete dryness." We may differ about off, the result is, to conrert substantially the whole of the the complete dryness. If aniline is mixed with dry aniline into red dye. Substantially, we use that process. arsenic, and the mixture is allowed to stand, no colour We do not use the exact proportion of water the patent will be produced, nor would there if water was present. states ; we use the smallest quantity we can possibly do The application of heat is necessary for the production of with, which saves time in boiling off. The use of water the colour. If the arsenic acid were anhydrous, practically is not necessarily essential to the conversion of acid and no colour would be produced. Medlock's process, as we aniline into the arseniate of aniline. The arseniate of perform it, produces the colour. On the large scale, we aniline would be formed whether the arsenic acid was in a do not boil the arsenic acid to dryness-to an absolute solid or a liquid state. It is easier and cheaper to use the powder, or perfect dryness. We use it in a fluid state. liquid solution of arsenic acid, and it is less dangerous We mix, in fact, a solution of dry arsenic acid and aniline than it is to boil that liquid down to a dry state. The together. The weight of water present is considerably main point is saving the men's health, but I admit that it less than that of the arsenic acid. There is about 30 per is a little cheaper. cent. of water and 70 per cent. of arsenic acid. The Re-examined by Sir F. Kelly: Dry arsenic acid is presence of water at the time of mixing is not absolutely known as an article of commerce. We had manufactured essential to ensure success.

and sold it before the date of Medlock's patent. I believo By the Lord Chief Justice Cockburn : We use water, it is largely used in calico-printing. We do not mix that because it is not so dangerous to the workman; it is more dry arsenic acid with aniline. Practically, we use the convenient, and it is cheaper. We do not get more dye, solution-the dry arsenic acid in solution in water. but it saves the expense of boiling down.

Lord Chief Justice Cockburn: Does it continue, when in By Mr. Hindmarsh : It is essential that an arseniate of a state of solution, to be dry arsenic acid ?-Witness: No, aniline should be formed in the process ; but mechanical my lord. water is not necessary for the formation of the arseniate. Sir F. Kelly: Dry arsenic acid is still in existence, though I am quite sure that I have made arseniate of aniline with in a state of solution. out water.

Lord Chief Justice Cockburn: No, no; arsenic acid in By the Lord Chief Justice Cockburn : The bottle I have solution is not dry arsenic acid. in my hand contains dry, but not anhydrous acid, and I Sir F. Kelly : It is dry; at least, so we consider. can produce arseniate of aniline by mixing it with aniline. Lord Chief Justice Cockburn: The witness does not say The water present is water of constitution, but not mechanical water, and the whole of it enters into the Sir F. Kelly : If your lordship will allow me, I think I aniline to form arseniate of aniline. Mechanical water can show that it is. The distinction is as perfect as possible. would not combine with the arseniate of aniline produced. (To the witness) : In the solution, does the water at all

By Mr. Hindmarsh : I do not know in what proportions combine with what you call “dry arsenic acid ” ?arsenic acid and aniline unite to form arseniate of aniline. Witness : No more than in a solution of common salt in We use in practice about equal proportions. The whole water. of the arsenic acid, practically, is then converted into Lord Chief Justice Cockburn : The solution implies that arseniate of aniline. There may be free aniline. I do not it is only a mechanical combination. know to a per centage how much water there is in what Sir F. Kelly : Whereas, the water which exists in the we call dry areenic acid. Our workmen know the exact dry acid, and which distinguishes it from anhydrous, point at which to stop the boiling. Arsenic acid is very is in chemical combination - Witness : In constitudeliquescent, and rapidly absorbs water from the atmosphere. tion. That is the distinction between water of con

Mr. Hindmarsh : Suppose arsenic acid to be made stitution and water of solution. There are three coneither according to Graham or Fownes, and you wanted ditions or states of arsenic acid :-There is the anhydrous, to keep it dry, would you not exclude the atmosphere or acid absolutely free from water; there is the dry, from it :-Witness: According to Graham, it is anhy, which has a certain proportion of water, but in condrous, and, therefore, I do not think it necessary to stitution or combination; and what we may call the wet, exclude the atmosphere.

or acid held in solution. We can, and have used the Mr. Ilindmarsh : Does he not say it absorbs moisture ? acid in the second condition for the production of the two - Witr($3: That may be an error.

dyes; but it is more advantageous to use the solution with Mr. Hindmarsh: But does he not say so :-Witness: about one-third, or thirty per cent., of water. In this case, It cannot be anhydrous, and yet have a great affinity for all the mechanical water comes off before the colour is water--I am speaking of anhydrous arsenic acid. Mr. produced ; and it is, undoubtedly, the dry arsenic acid of Graham may be inistaken. I applied for a patent, Lut, as commerce which operates on the aniline to produce the

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