Obrazy na stronie

Notices of Patents.


Sept. 29, 1865.


proved composition for coating iron or wooden ships' bottoms.”-August 16, 1865.

2140. A. Watt, Putney, “Certain improvements in GRANTS OF PROVISIONAL PROTECTION FOR soap.”--August 18, 1865. SIX MONTHS.

2246. W. T. Read, Great St. Helens, London, “ Im

provements in apparatus for stopping bottles.” Communicated by Mr. VaUGHAX, PATENT AGENT, 54, Chancery 2248. W. E. Newton, Chancery Lane, “ An improveLano, W.C.

ment in the manufacture of paper pulp.” A communica2123. 0. Laurence, Euston Road, “A new medicine tion from J. B. Brown, Peckshill, New York, U.S.A.for the cure of the diseases of the stomach (dyspepsy, August 31, 1865. cardialgy, indigestion) and the hæmorrhoids."-August 2252. T. Lomas, North Shields, “Improvements in the 17, 1865

separation of sulphide of iron from coal and carbonaceous 2129. G. H. Smith, North Perrott, Somersetshire, “An matter."-September 1, 1865. improvement in dyeing and preparing hemp and other 2266. C. Reichen, Lincoln's Inn Fields, “Improvefibres for the manufacture of yarns and fabrics."-Augustments in preparing charges for firearms and for blasting.” 18, 1865.

-September 2, 1865. 2150. J. B. Austin, Victoria Wharf, Blackfriars, "Im- INVENTION PROTECTED BY THE Deposit OF A COMPLETE provements in apparatus for stopping bottles.”—August


2314. J. Casthélaz and N. Basset, Rue St. Croix de la 2163: 'J. G. Avery, Regent Street, " A new composition Bretonnene, Paris, “ Improvements in the manufacture of suitable for use as paint and protective coating.”-A com- oxalic acid.” – Recorded Sept. 9, 1865. munication from W. Potter, Saratoga, U.S.A.-August

NOTICES TO PROCEED. 22, 1865. 2101. J. G. Dale, Warrington, and R. S. Dale, Man in the manufacture of iron.”-A communication from J.

1793. J. M. Macrum, Knightsbridge, “Improvements chester, “ An improved preparation for the prevention of Williams and J. Copley, Pennsylvania, U.S.A.—May 7, forgery of bank cheques, bills, and other documents.”Aug. 14, 1865.

1865 2187: C. A. Watkins, Greek Street, Westminster, “Im


J. A. Leon, G. Tegsimond, and J. Kissack, provements in apparatus for supplying carbonic acid

Liverpool, .* Improvements in apparatus for filtering sugar to casks and other vessels from which beer, wine, and and other liquid solutions.”—August 4, 1865. other fermented liquors are drawn.”

2095. H. Woodward, Cannon-street, “ Improvements in 2191. J. Moule, Hackney-road, " An improvement in carburetting coal gas and manufacturing artificial gas, and the treatment of tar and other substances suitable to be in the machinery or apparatus employed therein."used in the manufacture of paint, and for other purposes."

August 12. 1865: -dug. 25, 1865.

2203. H. A. Bonneville, Paris, “Improvements in the 2194. J. A. Wanklyn, London, "Improvements in the construction of apparatus for distilling and rectifying manufacture of violet dye-stuffs."

alcohols."- A communication from F. D. Savalle, Paris. treatment of certain products obtained in the refining of in the manufacture of coal gas."— May 6, 1865. 2195. J. Fordred, Blackheath, “Improvements in the August 28, 1865;

· 1266. J. Swindells, Wigan, Lancashire, " Improvements petroleum and of other hydro-carbon oils.”-Aug. 26, 1865. 2206. H. A. Bonneville, Rue du Mont Thabor, Paris, lothian, N.B., “ An improved composition for coating iron

1278 J. C. C. Halkett, Cramond House, county Mid“ Improvements in dyeing and fixing colours in fibres,

or other vessels, and for other similar purposes.”-- May 9, yarns, and fabrics." A communication from A. Jeannolle, Commune de Clichy la Garonne, France.- Aug. 28, 1865.

1865 2216. A. Gurilt, Birmingham, “ Improvements in con

2096. R. A. W. Westley, Camden Road, Camden Town, densing and utilising sulphurous smokes and vapours, and receptacles for storing, preserving, transferring, and dis

“A combination of improved inethod, apparatus, and in apparatus to be used for that purpose."'Aug. 29, 1865: charging certain fluids for sanitary and protective pur

2229. W. Crookes, F.R.S., Wine Office Court, Fleet Street, Improvements in extracting and separating gold France.- Aug. 14, 1865.


A communication from H. Pinkus, Boulogne, and silver from their ores or matrices, and in the treatment of mercury employed for such purposes."

1405. J. H. Johnson, Lincoln's Inn Fields, “An im2231. J. H. Johnson, Lincoln's Inn Fields, “Improve- proved apparatus for freezing, icing, and cooling liquids.” ments in tanning and in the preparation of extracts to be a communication from H. Ñ. Dullmaque, Paris. used therein." °A communication from E D. Coëz, Paris. J. F. Powell, Albion Place, Hyde Park, "Improvements

1409. R. Muller, Dartford, A. T. Weld, Gravesend, and -Aug. 30, 1865.

in the preparation of materials to be used as substitutes for W. E. Newton, Chancery Lane, “Improvements animal charcoal.”—May 22, 1865. 2247: in obtaining spirits of turpentine, rosin, pitch, tar, pyroligneous acid, and other products from wood.” A com

1507. W. Clark, Chancery Lane, " Improvements in the munication from A. H. Emery, New York, U.S.A.- ing and heating purposes, and in apparatus for the same.

means of carburetting or treating aëriform fluids for lightAug. 31, 1865.

2267. H. Ellis, Bangor, North Wales, " Improvements A communication from H. A. G. du Vergiers, Marquis de in the manufacture of compounds of silica, and in the

la Rochejaquelin, Paris.-June 1, 1865. production of silicated alkaline inks, colours, and dyes.” for the manufacture of printers' rollers." —June 24, 1865.

1694. F. G. David, Paris, " An improved composition -Sept. 2, 1865.

2289. T. Nicholson, Gateshead, county of Durham, “An improved process of, and apparatus for, making Metallic Capsules. We call the attention of our caustic liquor or caustic lees.”—Sept. 6, 1865.

readers to the announcement of a meeting to be held at 2064. C. West, Qucen's Place, Kennington Road, 17, Bloomsbury Square, on October 5, to take into con“ An apparatus for giving immediate warning of undue sideration the present position of chemists and druggists heat, whether occasioned by fire, spontaneous combustion, in reference to the sale of capsuled articles. Recent proor any other causes ; of leakage in ships, and of the ceedings have rendered united action on the part of the sudden irruption of water, and of the accumulation of trade absolutely necessary. The best course that could be choke-damp in mines."-August 9, 1865.

adopted would be a continuation of that already recom2120. S. Parry, Leadenhall Street, “A new and im- ! mended-piz., to refuse to retail all capsuled articles.


MiscellaneousAnswers to Correspondents.

Sept. 29, 1805.

dates, not exceeding twenty years of age, is awarded an CORRESPONDENCE.

exhibition of 30l., to the second one of 201., ard to the

third one of 15l., all for two years; to the fourth candiContinental Science.

date a prize of 1ol. in books or money, and to the fifth PARIS, Septen.ber 9.

and sixth prizes of gl. in books, philosophical instruments, An ingenious piece of parlour magic has lately been intro

or money. On page 139, col. 1, line 5 from bottom, "twenty

should be 'twenty-thrée.' Lastly, concerning duced by the conjuror Cleverman, who produces a snake, line 1, col. 1, of page 140, I must state that the division or what at a distance may pass for the coils of a snake, at into groups' was abolished by an order published about will. Something like a pastille is placed on a plate, a last December, and the subjects are now numbered conlight is applied, and in a moment the pastille swells up, secutively, and one gold, one silver, and two bronze medals and seems to uncurl itself, and something resembling a given in each subject.” snake appears on the plate. The preparation made use of

Dr. Hofmann's “ Introduction to Chemistry."is sulphocyanide of mercury (mercurous sulphocyanide), The new Introduction to Chemistry, Experimental and which, as your readers will know, swells up when heated, Theoretic," which was announced last spring as in preparaand gives a very bulky laminated mass. Some nitrate of tion by Dr. Hofmann will, we are informed, be issued in potash is mixed with the sulphocyanide, so that the heat a few days. We hear that Dr. Hofmann has again availed may be applied within the mass, and the snake-like ap- himself of the colloboration of Mr. F. 0. Ward, and in pearance of the residue is caused by the form in which the this work we may look for a Scientific pendant to the mixture is made up. Since vapour of mercury is given off admirable treatise on Applied Chemistry published by the in the combustion, it will not be advisable to repeat this

same authors as the "Report on Class II., Section A., of experiment many times in one evening in a small room.

the International Exhibition." The lectures Dr. HofStill less is it advisable to swallow one of the pastilles, as I read in Les Mondes a certain Prince o— did, and so stituce the framework of the book, which, in its expanded

mann delivered last spring at the Royal Institution connearly killed himself. The dose did not prove fatal to the form, will present a full exposition of the new system of Prince; but it did to a tapeworm he had the misfortune notation, and the modern doctrines of atomic and molecular to have associated with him. It must not be inferred from

construction. this either that sulphocyanide of mercury is a safe remedy obscurity, and to many the new doctrines are quite a

The subject is confessedly one full of for tapeworm. It is really a most virulezt poison, and if sealed book. It is, therefore, a matter of congratulation these toys come to be sold in England, the purchasers that a profound chemist like Dr. Hofmann, and a luminous should be particularly cautioned not to leave them in the writer like Mr. F. O. Ward, have been engaged conjointly way of children. As made up here, they are not unlike in the elucidation of the difficulties. We look forward to lumps of pâte de guimauve, and the silly young Prince 0

the publication of this treatise with great interest. By began to eat one, mistaking it for a bonbon

the kind permission of Dr. Hofmann, we shall shortly be

enabled to give our readers a chapter or two of the contents, American Manufacture of Soda from Cryolite. illustrated with the original woodcuts. To the Editor of the CHEMICAL News.

Preparation of Oxygen.--Mr. R. W. Artleet, Sın, - Allow me to trespass on the space of your valuable writing to the British Journal of Photography, says : paper by making a remark concerning a letter in your lasting oxygen by the action of peroxide of cobalt on solution

Having experimented on the valuable process for obtain. number the manufacture of soda from cryolite, and thinks the of hypochlorite of lime, with the view, among other things, importation of soda ash and caustic soda from England of ascertaining what other substances might be possessed into North America would be at an end if cryolite could of the curious powers of the peroxide of cobalt, I have be obtained in sufficient quantity.

found that moist peroxide of iron or oxide of copper will Now, I can state, on most reliable authority (my answer the purpose. These substances, in the repeated informant is one of those German manufacturers who trials I have made, have caused the evolution of a volume have a contract for part of the cryolite, and could not of oxygen equal to that obtained by means of the oxide of have any imaginable motive for imposing on me), that the cobalt, and, like it, they lose none of their efficiency by entire annual yield of the cryolite mines in Greenland is

use. The only difference I have observed is that, perhaps, 10,000 tons, and that it is impossible at present to work the oxide of iron requires rather the highest heat to cause them for more than that. Half of this quantity, or 5000

an equally rapid disengagement of gas. The oxide of tons, are contracted for by an American firm, and the copper answers perfectly, and if the oxide be not at hand, other half by various (three or four) manufacturers in

a few drops of nitrate of copper may be added to the Denmark and Germany. Now, if you take in account hypochlorite of lime solution, and the gas will be given off the fact that the whole of those 10,000 tons would not cover

abundantly immediately on the application of heat. I by far the demand of a single of the large firms on the have also tried peroxide of manganese, but have not yet Tyne or in Lancashire, it will be apparent enough that that it does not accomplish the end in riew so well as the

sufficiently investigated its action. I may, however, state there is no foundation whatever for the apprehensions of other substances. The quantity of oxygen liberated is your correspondent.

I am, &c.
Geo. Lunge, Ph.D.

smaller, and permanganic acid is formed.' South Shie'ds, Soptember 26.


J. B.-Had better consult a medical man.

99 is thanked. For the two errors, not corrected, though evident

enough, we hardly consider ourselves responsible. One is in the Prizes and Honours at the London University. original French; the other in a copy furnished by the speaker.

Formation of Acetylene.-In answer to a correspondent, inquiring -An esteemed correspondent sends us the following cor. for the details of Dr. Odling's experiments, the Doctor writes as rections of the statements in our last respecting the prizes follows :-"I gave an account of my experiments on the formation of at the London University :-" If you examine the calendar acetylene at the Cambridge meeting of the British Association. There you will find that in January last the special honours reaction was also mentioned in Sir Wm. Armstrong's introductory

is a very short note on the sulject in the report of that meeting; the examinations were abolished, and the candidates placed addres - at the Newcastle meeting, and in the appendix to the first in the honours division ranked

according to their proficiency volume of Watt's “ Dictionary of Chemistry. I have never published in the subjects collectively. To the first of such candi. I the details of the experimenis, having intended first to work up the i



Oet. , 1865.
The Action of Aldehydes on Rosaniline.


I have not hitherto succeeded in isolating the diphényAND ANALYTICAL

lénic diamide which figures in this equation, but the CHEMISTRY.

microscopic inspection and chemical analysis of a great

number of chloroplatinates puts it beyond doubt that The Action of Aldehydes on Rosaniline," by the decomposition of enanthic rosaniline at least two by M. HUGO SCHIFF.

amides are formed, one of which must have an equivaI have in former notes described the products of the lent lower than that of the above compound. action of aldehydes on some monamines (amylamine,

The action of benzoic aldehyde, slow at 90°-1000, aniline, toluidine) and on toluylenic diamine. We now furnishes, in the first place, a violet mass, which, accord purpose giving the results of our researches on the ing to the analyses of chloroplatinate, seems to contain action of aldehydes on a triamine-rosaniline.

the intermediate compound toluydenic rosaniline The action of aldehydes on aniline red was ascertained in 1865 by M. Lauth, who in this way obtained violet

N,,H=6H23Ng. and blue matters. M. Lauth supposes that aldehydes

H act on aniline red as reducing agents; but this is not the The complete substitution is with difficulty effected at case, they act on rosaniline as on other amines; the 120°, and gives a crystalline product, copper coloured water is eliminated, and typical hydrogen substituted by and possessing almost exactly the properties of the the diatomic residues of the aldehydes. Salts of ros- enanthic compound. aniline may be operated on directly. Onanthic aldehyde I had hoped that the decomposition of rosaniline by acts at the ordinary temperature. By pouring the alde- benzoic aldehyde would furnish one of the terms interhyde on crystallised acetate of rosaniline, the crystals lose mediate between hydrobenzamide and amarina, described form and lustre and absorb the liquid. Fresh quantities in a previous note, but its decomposition is not analogous of the aldehyde should be added, while triturating the to that of the cenanthic compound. The decomposition mixture in a capsule, so long as absorption takes place. in this case takes place very slowly, even at 150° to 160°, A crystalline mass is thus obtained of a coppery appear- and in presence of an excess of benzoic aldehyde. A ance, moistened by water formed during the reaction. dense yellow liquid is finally obtained, which gives up Alcohol gives a solution of a magnificent blue colour, its excess of aldehyde on treatment with alcohol, leaving with all the properties of a colouring matter. Caustic a sandy powder, very little soluble in alcohol and ether, alkalies precipitate red crystalline flakes, giving crys- insoluble in caustic alkalies and acids, even when contalline salts with acids, coppery in appearance, insoluble centrated, but furnishing a chloroplatinate with from 11 in water, and containing the hexatomic base triænan- to 91°5 per cent. of platinum. The final action of acetic thylidene-dirosaniline

aldehyde on acetate of rosaniline causes the formation 26,= E., H, N,

of an analogous substance. These substances neither 1 36, HM

possess the properties of toluenic diamides nor those of formed according to the equation

a derivative of leucaniline.

In conclusion, I would observe that the products of 2N, {€34, +30,47,9 = 3H,9+N, {:H substitution furnished by aldehydes with rosaniline supThe base furnishes several chloroplatinates, it combines port the formula by which M. Hofınann denotes the con

nexion between aniline red and blue. with weak acids, and even with carbonic acid.

These salts and the hydrate of the base readily decompose below 100° C., especially in the presence of a slight Mineralogical Chemistry: Studies on the Immediate excess of enanthol, producing a yellow resinous mass Analysis of Minerals, by M. G. LECHARTIER." containing free acid. "The transformation may be effected ANALYSES made by the same chemist, of different without the least loss of weight and without disengage- varieties of the same kind of mineral, frequently prement of a gas, if the acid be not very volatile. In its sent considerable differences in their results. The cause properties the product resembles the compounds obtained of this diversity is to be traced to the impurity of the by the action of benzoic and ænanthic aldehydes on substances analysed. A careful observation of natural aniline, toluidine, and toluylene-diamine. Iu fact, the crystals shows how difficult it is to obtain an isolated greater part of the dense mass consists of a resinous mineral substance. Sometimes these crystals are mixed diamide, ananthylidene-ditoluene-diamide

with foreign matters, sometimes they have undergone a 6,66

mere or less radical alteration. Often the pure crystals N, CH, = €2,H26N,.

exist only in very small quantities, in rare specimens, to

be found only in very few places. When they can be This amide can hardly be said to possess basic pro- found they serve to determine the chemical composition perties, but it furnishes a yellow chloroplatinate, which will be the typical composition of the whole €2H26N2.HPt.Cig.

mineral. But it remains to be shown that the composiWere we to admit Dr. Hofmann's formula for rosaniline, tion of the other varieties which are less pure is identical. N,(C,H.26.1.H2),

Hence the necessity of purifying crystals without alterit would decompose with ænanthol, according to the ing them. It is at all events needful, by carefully

observing the impurities mixed with them, by analysing equation,

them, to show cause for the differences between the G.H.

results obtained and the composition of the mineral type. 2N, 26,H+ 36,4140

M. Ch. Sainte-Claire Deville, in his great work on H,

feldspaths, proves the importance of isolating, by careful CH, 6,H

sorting, the matter to be analysed. It was by devoting N, EH + 2N, CH + 3H20.

a considerable length of time to this operation that he

discovered the simple chemical connexion between the • Comptes Rendus, lxi., 45.

Bulletin de la Société Chimique, 1865. VOL. XII. No. 305.-OCTOBER 6, 1865.


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Oct. 6, 1865.


On the Strength of Solutions of Phosphoric Acid.

numerous minerals of this group, and added several varie- At the temperature given by the gas furnace, a reacties to the list, which had been separated from it. tion takes place between the carbonate of lime and the

Without these precautions, it would be found neces. silicate; carbonic acid is disengaged, and the oxide of sary, after the most careful analyses of matters supposed iron is reduced. Continue the action of the hydrogen to be pure, to admit different compositions for the until the weight remains constant. A current of dry varieties of the same substance, all having the same air afterwards rapidly oxidises the iron. Fuse the crystallographic characteristics, or to admit that two mixture in a platinum crucible, and analyse the glass in bodies, such as silica and aluminia, are isomorphous, the usual way. The weight of iron is determined in the though no fact in chemistry justifies such an hypothesis. analysis. The first of these results is produced by the staurotide ; the second by amphiboles.

Accidental Formation of Sulphide of Silver (Argyrose), Such are the difficulties which I have endeavoured to

by Dr. T. L. Phipson, F.C.S. overcome by these researches, made in the laboratory of the Ecole Normale Superieure. As a pupil of M. Henri ABOUT eighteen months ago I filled a silver match-box Sainte-Claire Deville, I have endeavoured to apply his with the common large French matches which are used lessons, and have throughout been much indebted to his in the cafés, &c., at Paris. On my return to London advice.

this box lay for many months in a drawer that was Analytical Processes.—I followed exactly M. H. rather damp; On opening the box recently, I was surSainte-Claire Deville's analysis of silicates, described in prised to find the inside lined with very brilliant crystals the Annales de Physique et de Chimie, xxxviii., 5.

of a black colour and metallic lustre, which reminded The purity of the isolated elements, and especially of me at once of some specimens of silver ore I had received silica and magnesia, has always been acknowledged. I a few months back from the Don Pedro mines of Mexico. dissolved the silicate in pure hydrofluoric acid, and ob- I had no doubt these crystals-modified octahedra of the tained crystallised hydrofluate of fuoride of potassium. first system-were argyrose (or silver glance) accidentI slowly evaporated the hydrofluoric liquid with a few ally formed. On examining them with a powerful lens, drops of sulphuric acid added to it. The sulphates re

which enabled me to make a drawing of their crystalmaining alone in the capsule were calcined at red heat, line form, and finding afterwards that they contained and the weight of oxides subtracted from the first weight about 87 per cent. of silver, this supposition proved obtained. A similar operation was performed with mag

exact. It is, therefore, not improbable that this mineral nesia, which was dissolved in nitrate of ammonia. may have been formed in nature by the prolonged action

Determination of the degree of Oxidation of of sulphurous vapours upon metallic silver. Iron in the Silicate. In the analytical process hitherto employed the mineral is attacked by borax, or boric on the Strength of Solutions of Phosphoric Acid of acid, dissolved in an acid, and protoxide of iron estimated in the solution by means of a standard solution of

Various Densities, by Mr. JOHN WATTS, Senior Bell

Scholar in the Labor atorics of the Pharmaceutical permanganate of potash. In this operation it is indispensable to avoid oxydising bodies and reducing gases, The utility of a table which shows at a glance the per

Society. and this is very difficult.

I have tried to find a process by which might be de- centage strength of a solution whose specific gravity is termined, by means of the balance, the quantity of known, will at once, I think, be admitted by all. The oxygen combined with the iron. Were the determina- force of this is shown by the fact that, many years ago, tion to be made on free oxide of iron, it would suffice to MM. Bineau and Otto compiled the first table of the reduce a given weight of dry oxide in a hydrogen kind, sulphuric acid being the substance operated upon ; current.

this was soon afterwards followed by nitric and hydroThere are some silicates on which hydrogen has no chloric acids by Dr. Ure; and still more recently by action, among them are staurotide and augite ; on others another for ammonia. The other alkalies, potash and its action is incomplete, but on heating the silicate, soda, have also been tabulated by Dalton and Funnermixed with sufficient carbonate of lime to render it mann; acetic acid by Dr. Mohr, and alcohol by attackable by acids, in a hydrogen current, the oxide is

Fownes, These, I believe, are all which, up to the perfectly reduced. The advantage of this process is present time, have been so worked upon. that the operation is performed on the very substance Knowing the great advantage such tables present to serving for the complete analysis of the silicate; it is the practical chemist

, more particularly in saving of effected at the same time that the mineral is attacked by time and labour, I undertook, as a subject for the Pharthe lime.

maceutical Conference, to compile a table of phosphoric The oxygen being determined by the difference of acid, so as to exhibit at once the relation between its weight, all the volatile elements must be eliminated, by density and its strength. Although a table for heating the mineral to redness in a pure and dry current phosphoric acid is not so indispensable as one for sulof nitrogen, and the water, if there te any, collected on phuric or nitric acids, its use in the arts and manufaccoming from the tube and weighed.

tures being much more limited, still phosphorio acid is To reduce oxide of iron, mix the matter thoroughly coming into much greater use, at least in medicine, and with a given weight of pure carbonate of lime, and put any one who has had the work of making

the “syrup of the whole in a platinum vessel, previously tared, in a

phosphates” which are now so fashionable, knows the stoppered glass tube. Weigh the mixture, after having advantage accruing from the possession of a ready dried it at a low temperature. Place the vessel, by

means of obtaining a knowledge of the strength of his means of a slide in a platinum tube, which heat over a gas

In the compilation of a table of this furnace. Pass into the apparatus a regular current of kind, the first thing is to know at what specific gravity hydrogen, purified by its passage through a fask filled to start; accordingly, finding that a thick syrupy acid with fragments of potash, and a glass tube containing of 15 sp. gr. contained nearly so per cent. real Pos, I platinum black, heated to a little below nascent red heat. * Read at the meeting of the Pharmaceutical Couference,




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Oct. 6, 1865.
On the Strength of Solutions of Phosphoric Acid.

161 made that the starting point and proceeded regularly red lead (2PbO + Pb02), and dissolving out the protoxide downwards as far as sp. gr. 1.006. The interval between with dilute nitric acid, washed well the resulting bin

these two numbers contains 47 specific gravities, there- oxide; this, by careful ignition over an air-flame, loses i fore 49 in all, and as each sp. gr. was analysed at least its extra oxygen atom, and passes with incandescence to

three times in order to obtain a correct mean, it entailed the state of protoxide. Working with oxide prepared

the work of about 150 analyses. The table, when com- in this manner I obtained highly satisfactory results, and Spleted, stands as follows:

subsequently used this method only for the completion

of the analysis of the table. By examining the gradaSpecific Per. Specific Per- Specific Per- specific

tion of the numbers on the table, we see that the pergravity centage gravity centage gravity centage gravity centage

centage increases or decreases regularly according as the 471,508 49.60 1369 39'21 1'236 2763010095

specific gravity rises or falls, proving that the strength

12'18 1'492 48.41 1356 38.00 1.226 26.36 1081 10'447

can be correctly deduced from a knowledge of its density 1476 47'10 1°347 37-371-211 24*79 14073

and that, unlike acetic acid, it presents no anomaly in

9:53 1464 4563 1339.1 3674 1197 23:23 1066 8.62 this respect; also, that when a strong acid is diluted 10453 4538 1'328 36.151.185 226071056 7'39

with water, though a considerable quantity of heat is 1 442 44'131315 34.82 1'173 20-911047 6.17 evolved, no condensation in volume follows. The correct. 1434 43-9514302 33:49 1'162 | 19'73 1031 4'15 ness of the numbers may be also somewhat checked in 1'426 43°28 | 1*293 32'711'153 18.81

3'03 the following manner :- 1'418 42.61 1285 31094 1:144 1:8914014 1'91 Take 100 fluid grains of 1.508 acid, this will weigh 1'401 41.60 1.276 31.0341-136 16'9514006

*790 1508 grs., and contain 74.79 grs. by weight of PO, 1*392 40.86 1.268 30°13 1124 | 15.64

dilute this with 100 fl. grs. of water, the whole will weigh 1'384 40'12 1257 29.16 1'113 14633 1.376 ! 39•66 | 1-247 | 28-24 | 1'109 | 13:25

250.8 grs., and contain 74.79 grs. by weight of POs; each

100 parts by weight will be therefore of sp. gr. 1'254, I would next notice the method employed for its and contain theoretically 29.7 parts by weight of acid; analysis. Now, after essaying and testing the various by referring to the latter sp. gr. on the table, we find advantages of a great many different processes, of which by experiment such number to contain 29°16 per cent. I will speak hereafter, I came to the conclusion that, Again, 100 f. grs. of acid 1.285 sp. gr. will weigh.128.5 with a pure solution of phosphoric acid, no method is grs., and contain 41'03

grs by weight of PO, ; diluted more simple, more accurate, or less liable to error, than with 100 8. grs. of water, will weigh 228.5 grs., and conthe method employed in the British Pharmacopæia- tain 41'03 gis. of acid, being of sp. gr. 1*142 ; each 100 viz.,." the evaporation down of a weighed quantity of the parts of this sp. gr. should contain, then, 17'9 by weight solution, with a known excess of pure protoxide of lead." | of Pos. Reference to the table shows us 17-89 per cent.

I confess I was somewhat disappointed when first em- I have checked a great many numbers in this manner, ploying this method, owing to the discordant results and they all come correct. obtained, notwithstanding that at first sight it seems ex. The temperature at which all the specific gravities ceedingly straightforward and plain ; but I afterwards were taken was 15'5 C. (60° Fahr.). This is, of course, found it entirely arose from not operating with pure an important point in using the table, as the volume of oxide. I had used the commercial article, and though liquid varies considerably according to the temperature ; previous to each analysis it had been carefully ignited, and as at different heights of the thermometer comparithere nevertheless remained so much carbonate and other son of volumes no longer holds good, consequently comimpurities, as to render it practically worthless, no two parison of percentages would be equally fallacious. results agreeing nearer than 2 or 3 per cent.

Very little more remains to be said, as this is not a Finding this to be the case, I looked about for some comprehensive subject which requires much dwelling other substance to use instead, and for this purpose tried upon. I might

add that the acid used was prepared the oxide of zinc. Analysis with this latter oxide gave from common phosphorus in the ordinary manner ; but perfectly accurate results as regards numbers, but was, I have since made several samples of acid from amorhowever, open to a great ohjection, inasmuch as the phous phosphorus as first mentioned by Mr. Groves, and phosphate of zinc formed readily fuses, and upon igni- decidedly prefer this latter method; the phosphorus is tion towards the end of the analysis to get rid of the readily acted upon, entails no danger in the process, and last traces of water, the phosphate fusing, and adhering a product is obtained in a few hours which ordinari.y tenaciously to the bottom of the crucible, from which it would take as many days. One little objection appeared, cannot be subsequently removed, entirely spoils it for a which is apt to make one think that the product is not second operation. Oxide of magnesia answered no better, absolutely pure, viz., that in the concentrated state it for this, unlike the oxides of lead and zinc, forms a

was more or less coloured, possessing a brownish or hydrate when put into water; and, as is the case with yellow tint; this might have arisen from the particular many magnesia salts, either the last traces of this water specimen of amorphous phosphorus operated upon : of bydration, or the atom of basic water assimilated when probably another sample would not show this defect, neutralising the PO, is so difficult to totally expel, even Lastly, I think I have shown, as far as practicable, after powerful ignition, that one can never be certain the corrections of the table in question ; and I know that the whole of the water is driven off unless the cap; this, that in quantitative analysis generally, and more sule has been

allowed to cool and re-ignited several especially when work is published for the use or guidance times, which, with such a number of similar analyses, of others, as in the present instance, it behoves me causes much unnecessary trouble. ... I tried also to accept only thoroughly-substantiated and verified the volumetric nitrate of uranium process, but as the results, else an incorrect analysis, while it brings one's results never approach nearer than five to six per cent., own name into disrepute, at the same time misleads and a discrepancy too great to be allowed in a case like this, falsifies the labours of others. It only remains now to it was given up. : . Determined then to revert again to be seen whether the table prove in practice as useful oxide of lead, and to prepare a pure oxide myself, I took as it was anticipated to be. + Ph. Br.

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