« PoprzedniaDalej »
Oct. 20, 1876.
167 is decomposed by ignition with charcoal powder. The The precipitate produced by arsine in the water solution preparation of bromide of potassium and the bromides of of mercuric cyanide is very unstable, decomposing, in a iron is conveniently combined with the manufacture of few hours into Hg and arsenious and hydrocyanic acids at bromine. Since 1867 Franck condenses bromine in a set the ordinary temperature. The precipitate is so finely of three Woolff's bottles, the first of which, slightly cooled, divided that it passes completely through filter-paper. receives liquid bromine, whilst the second contains bro Stibine appears to be a still more energetic reducing-agent mide of potassium or ferrous_bromide, and the third on mercuric cyanide than phosphine or arsine ; a rapid potash-lye or iron-turnings. The chloriferous bromine stream of stibine (SbHz), prepared from (Sb2Znz), provapours escaping from the first slightly cooled receiver | ducing a precipitate of metallic mercury in either aqueous pass through the solution of bromide and are freed from or alcoholic solutions. their chlorine, in the place of which bromine escapes from
W. R. H. the bromides and arrives in a pure state into the iron- Royal College of Chemistry. turnings or the potash-lye contained in the third bottle, in which pure bromides are at once obtained.
We have already mentioned that a large proportion of NEW METHOD FOR ASCERTAINING bromide of potassium is obtained from the ferroso-ferric | THE EXACT QUANTITY OF PURE ANTHRACEN bromide. The manufacturers of bromide of potassium are
CONTAINED IN CRUDE ANTHRACEN. not under the necessity of preparing the iron compound themselves from condensed bromine. It is obtained at
By MEISTER, LUCIUS & BRÜNING. the Stassfurt bromine works, and is sold in the form of a paste containing from 65 to 70 per cent of bromine. As The experience gained during the last few years with reit can be packed in vessels of stoneware and tinned iron gard to anthracen testing has induced us to abolish our and even in wooden casks, it is the most convenient form old test of October, 1873, and the appendix of 1874, and for the carriage of bromine, which, in the free liquid state, to issue a new and improved method, as follows: is difficult to pack and dangerous to convey.
Take i grm. of anthracen, place it in a flask with con(To be continued).
denser of 500 c.c. capacity, add to it 45 c.c. of glacial acetic acid, and heat to ebullition. To this solution (which is kept boiling) add, drop by drop, a solution of 15 grms.
of chromic acid in 10 c.c. of glacial acetic acid and 10 c.c. ACTION OF PHOSPHINE (PH3) ON MERCURIC of water. CYANIDE (HgCy2).
The addition of the chromic solution should occupy two
hours ; after which the liquid is to be kept boiling for When pure phosphine is passed into a solution of HgCyz two hours longer, four hours being required to complete in water or alcohol the gas is absorbed, a pale yellow pre- the oxidation. cipitate is formed, and hydrocyanic acid (HCy) is evolved. The flask with its contents is to be kept standing for This yellow precipitate quickly turns black on warming or twelve hours, then mixed with 400 c.c. cold water, and exposure to sunlight, with partial reduction to metallic again kept standing for another three hours. mercury. The alcoholic solution yields a better product The precipitated anthraquinon is now collected on a than the aqueous solution, the precipitate being of a much filter, and washed first with pure water, then with boiling brighter yellow colour, and not decomposing quite so dilute alkaline solution, and finally with pure hot water. rapidly as that formed in the aqueous solution.
The quinon is now washed from the filter into a dish, and It is so sensitive to light that it was found impossible to dried at 100° C. It is then mixed in the same dish with dry it, even in vacuo, without change of colour in the ten times its weight of fuming sulphuric acid of 68° Baumé superficial portions. After drying for thirty hours in (sp. gr. 1.88), and heated to 100°C. for ten minutes on a vacuo over oil of vitriol, a sample had a surface-colour water-bath. The quinon solution thus obtained is poured greenish black, the under part being still yellow. Quan into a flat dish, and kept for twelve hours in a damp place titative analysis shows it to contain Hg, P, Cy, and H.
to absorb water. When heated contact with the atmosphere it ignites Then add 200 c.c. of cold water to the contents of the at about 90° C., undergoing a kind of smouldering com- dish, collect the precipitated quinon on a filter, and wash bustion, a residue of phosphoric acid, mercury, and some first with pure water, then with boiling alkaline solution, difficultly combustible carbonaceous matter containing and finally with pure hot water. nitrogen, (probably "para-cyanogen ") being left. When The anthraquinon is now flaced in a dish, dried at heated in tube a little cyanogen gas and a phosphuretted 100° C., and weighed. After volatilising the quinon by hydrogen are given off, a residue of mercury and phos- heating the dish, it is weighed, with the particles of coal phoric acid, with carbonaceous matter, remaining.
and the ash. The substance is oxidised by nitric acid, but dilute HCI The difference between the two weights gives the weight and sulphuric acid do not seem to affect it.
of anthraquinon obtained, and it is to be calculated in the Carbon, hydrogen, and mercury combustions have given usual manner into anthracen. the following figures :--
Hoechst, a. M., October, 1876.
Prize in Industrial Hygiene.—An offer of a medal in Hg 84872
84076 connection with this subject has been made by Mr. BenH..
jamin Shaw, and has been accepted by the Council of the Phosphorus 5'47
Society of Arts. The medal will be of the value of £20, Nitrogen 5'00 (nearly) (soda-lime comb.) and will be awarded every fifth year. The terms of the
W. R. H.
offer are as follows: "For any discovery, invention, or Royal College of Chemistry.
newly-devised method for obviating or materially diminishing any risk to life, limb, or health, incidental to any
industrial occupation, and not previously capable of being ARSINE AND MERCURIC CYANIDE.
so obviated or diminished by any known and practically
available means." The first award will be made in May, A PRECIPITATE is also produced by arsine (AsHz) in alco-1877The latest date for receiving communications
will be March 31, 1877. holic solution of HgCyz, which has a red-brown colour, and is also rapidly affected by light, but not quite so easily precipitation of the anthraquinon, and the correction formerly made
* The increased quantity of water added ensures the complete as the phosphine compound.
is no longer necessary.
20, 1876. NOTES OF WORK BY STUDENTS OF | treated with an acid, or (pectate of lime) with a solution PRACTICAL CHEMISTRY
of lime. In China the Füh-ling is made into edible cakes, IN THE
which are frequently sold in the streets; it is also reported LABORATORY OF THE UNIVERSITY OF
medicinal in a variety of disorders. In America it has
also been used as an article of food, whence the name VIRGINIA.
The Report of the U.S. Department of Agriculture for
1870 (p. 423), in an article upon materials used as food
by the North American Indians, has the following notice Professor of General and Applied Chemistry in the University,
of this substance : (Continued from p. 149.)
“Tuckahoe or Indian Bread (Lycoperdon solidum).—Two
specimens of this fungus are in the collection of the (2.) Chemical Examination of Füh-ling (Lycoperdon Department of Agriculture—one from Nottoway Co.,
solidum) from China. By J. L. Keller, of Char. Virginia (fig. 1, plate 10), and the other from Leroy, lottesville, Virginia.
Kansas (fig. 2, plate 10). These singular fungous growths Among a number of interesting specimens which Mr. are subterranean and parasitic on the roots of large trees. Justus Eck, of London, was kind enough to present, some A piece of root is often inclosed in the mass. The form iwo or three years ago, to the laboratory collections of is irregularly globose, about the size of a man's head. It this University, was one of this curious material, accom- is very rugous and filled with cracks; the colour exter. panied by the following extract in reference to it from the nally is ashy black, in the interior white or nearly so, of late Mr. D. Hanbury's “Notes on Chinese Materia a starchy appearance, very firm, and breaks into irregular Medica :"
masses. The Kansas specimen is rounded in shape, with : Füh-ling; Pachyma cocos, Fries (Fungi); Lycoperdon a black, rough exterior, and a white and compact interior. solidum, Gronovius; Pé-fo-linn, Cleyer” '(Med. Sin., When broken it has the appearance of a mass of dried No. 189), Tafarinov (Cat. Med. Sin., pp. 2–23); Pun- dough, full of fissures and very granular. Booth and tsaon ; Indian Bread ; or Tuckahoe. A very large re.
Morfit's Cyclopædia of Chemistry gives the following under markable substance resembling ponderous rounded iubers the article of . Picquotaine,' a highly nutritious plant used having a rough blackish brown bark-like exterior, and
as food by Indians. It results from a disease of the consisting internally of a compact mass of considerable Psoralea esculenta. Its composition is as follows: hardness, varying in colour from cinnamon brown to pure starch, 81-80 + water, 12°50." The following
Nitrogenous matter, 4'09 ; mineral substances, 1:61; white. These tuberiform bodies, which in weight vary relative to the Tuckahoe are furnished by Dr. John from a few ounces up to several pounds, are found attached to the roots of fir trees, or sometimes buried in the Torrey : It was first brought to the notice of the public ground of localities where firs no longer grow. They by Dr. Clayton, who sent it to Gronovius under the name occur in South Carolina," in some of the northern and
of Lycoperdon solidum and as such described it in the western provinces of China, and in Japan. Their true
Flora Virginica about one hundred andtwenty years ago. nature is sufficiently perplexing. The older writers con
Next it was described by the late Dr. von Schweinitz, in sidered them to be a sort of China root (Smilax), a sup
his “Synopsis of the Fungi of North Carolina," under the position which their outward appearance certainly favours. Macbride, of Charleston, South Carolina, sent to the
name of Scleroticum cocos. About the same time Dr. but which is immediately negatived when we find them to contain no trace of starch. Loureiro and Endlicher are Linnean Society of London his observations on that content to describe them as tubers found upon the roots fungus. Without being aware of having been anticipated of fir trees. Other botanists have placed them among about the year 1819, under the name of Scleroticum gigan.
by Schweinitz I described it in the New York Repository fungi; Gronovius and Walter in the genus Lycoperdon ; Schweinitz in Scleroticum ; Okur and Fries in Pachyma. teum: I gave also a chemical analysis of it, showing The latest observations on the subject are some which that it is chiefly composed of a singular substance which were submitted to the Linnean Society by Mr. F. Currey I named sclerotine. Braconnot some years after this deand myself last year (1861) and published in the Linnean scribed the same principle, which he called pedine. In Transactions. The opinion there expressed is that these the Synopsis Fungorum of Fries, the fungus is called tuber-like bodies are an altered state of the root of the Pachyma cocos. In the Proceedings of the Linnean tree, probably occasioned by the presence of a fungus, the Society of London is an account by Rev. M. J. Berkeley mycelium of which traverses, disintegrates, or even oblite- of a large subterranean fungus that is sold as food in the rates the wood and bark. This mycelium appears under streets of Shanghai, undoubtedly the same as the Tuckathe microscope in the form of fine threads usually more
hoe.” or less mixed with bodies of irregular shape, somewhat
And in the Report of the same Department for 1871 resembling starch granules, but which are apparently (p. 98) occurs the following from R. T. Brown, Chemist to cells of the woody tissue in a more or less advanced state the Department: of disease and distortion. Nothing is known of the more “ Tuckahoe or Indian Bread.—This curious fungus developed form of the fungus represented by the mycelium. (Scleroticum giganteum) is quite common in many parts The American Füh-ling has been examined chemically by of the Southern States, where it is frequently used as an Professor Ellett, of South Carolina College, who has article of food.* To determine its nutritive value a stated it to consist entirely of pure peaine of Braconnot, specimen from Columbia, Virginia, was subjected to carebut I think its composition deserves some further investi- ful analysis in this Laboratory, with the following results :gation. I find that the pure white internal substance
« Moisture (which is quite insipid and inodorous) is very slightly
“Glucose (fruit sugar) 0'93 soluble in cold rectified spirit and in cold water, and not
2.60 more so when boiled in water, the solution in each case
17834 yielding a flocculent precipitate with acetate of lead.
"Nitrogen in an insol.com} 0-36 When boiled in a weak solution of carbonate of soda the
bination substance dissolves rather more freely, and the solution
“ Woody fibre
64:45 affords a scanty gelatinous precipitate (pectic acid) when
0'16 * They are by no means peculiar to this State. I have seen specimens found at various points from Virginia to Alabama on the Atlantic side of the country, and, as will be seen by the quotation from Report of the Department of Agriculture, they extend as far west as This is certainly an over strong way of stating the facts. SpeKansas.
cimens of the material in question are not very rare, and they are
CHEMICAL, NEWS,} Practical Chemistry in the University of Virginia.
169 “This analysis does not sustain the high reputation of correctness of the opinion of Messrs. Hanbury and Currey this substance as a food material."
as to the general nature of the substance, viz., that it The substance received from Mr. Eck being from China, represents woody fibre altered by the interpenetration of while all the above statements as to chemical composi. a fungus mycelium. In the specimen analysed by the tion refer to material from America, and these statements Chemist of the Agricultural Department the alteration differing so widely from each other, it seemed well to make seems to have been incomplete, leaving a good deal of a new analysis, which was done by Mr. Keller.
unchanged cellulose ; in the case now under notice the The specimen of Chinese Füh-ling examined was cellulose has nearly disappeared. The very small amount kidney-shaped, about 6 inches in longest diameter, and of nitrogen renders the notion of the whole mass being 31 inches in shortest, and weighed about two pounds and a simply an independent and developed fungus very unquarter. The rough, brownish black, bark-like exterior likely. was about an eighth of an inch thick, verging gradually Mr. Keller also made an analysis of the ash, to obtain into the perfectly white uniform mass inside. The whole which about 100 grms. of the substance was incinerated was compact and firm, but easily cut with a saw, and the at a very low temperature in porcelain crucibles placed fragments, after removal of the exterior crust, shewed but each within another of sheet iron serving as a hot-air little toughness and were easily crushed in a pestle and bath. The ash was tolerably free from remaining charmortar. A sufficient quantity was reduced to fine powder, coal. Chlorine, carbon dioxide, and silica were deterpassed through a sieve, and thoroughly mixed. This mined from the whole amount used; and after dividing powder yielded little soluble matter to either cold or hot the solution into two portions, sulphuric oxide and the water, but was much more freely dissolved by a dilute alkalies were obtained from the one, and phosphoric solution of hydrate or carbonate of sodium, the liquid pro oxide, ferric oxide, lime, and magnesia from the other. duced in each case giving a flocculent gelatinous precipi- | The analysis afforded :tate (corresponding in character to pectic acid) when
Pure Ash. treated with an acid or alcohol, such precipitate proving K,0 excessively difficult to wash. Starch and cane-sugar Nazo
2.062 (Deducting Sand, Charcoal,
967 and Carbon Dioxide.) were carefully tested for, but none could be found.
4:675 The quantitative analysis was made as follows:
2'192 Water was determined by prolonged exposure to 110°C.; Fe2O3 albuminoid matter was calculated from the amount of nitro
5*169 8.725 Mgo
11'375 gen, determined by combustion with soda lime. For the
0°700 Fe2O3 organic matters soluble in water the powder was exhausted cı..
0*724 P2O5 with water by repeated boiling, keeping the Aask full of
1'587 steam so as to exclude air ; the liquid rapidly filtered, and
1.642 evaporated (in a retort exhausted by a Bunsen's pump) to
Charcoal a small bulk. The solution was then divided into two
50*546 parts, continuing the evaporation of the one to dryness at 100° C., weighing the residue as soon as it ceased to lose
99-675 Deduc o equiv. to} 0-370
ci the other was separately evaporated to dryness, exhausted with dilute alcohol (which took up a little glucose), and the residue dried at 100° C. and weighed; this being
99.630 burned and the weight of ash plus the previously deter
99'512 mined weight of albuminoid matter deducted, the quantity The large amount of sand is not caused by want of of gum was found by difference. In the dilute alcoholic care in removing the exterior portions of the mass. With solution glucose was determined by Fehling's copper solu- a lens sparkling little siliceous grains can be detected on tion. The pecous material was dissolved out from what a perfeály clean cut surface of the interior. This again water had left by repeated boiling with a dilute (13 per accords with the idea of a fungoid growth pushing its way cent) solution of sodium hydrate, and precipitated by in a sandy soil into disintegrating woody tissue, and candilute sulphuric acid and alcohol, but it was found to be not at all be conceived of as a result of simple independent almost impossible to wash the slimy precipitate, and it vegetable growth. Part of the large percentage of silica could not have been relied upon as unaltered in weight found to be soluble, and perhaps of the iron also, may from the original insoluble pectous material, so that this very likely be also mechanically derived from the soil, but was estimated by difference. The cellulose left undis- how much we have no means of determining. solved by the sodium hydrate was treated with very dilute
(To be continued.) sulphuric acid (in the cold and for a short time only), then thoroughly washed with water, thrown on a weighed South African International Exhibition, 1877.filter, dried at 100° C., and weighed; after burning the An International Exhibition will be held in Cape Town in weight of the ash was deducted. The results were :
1877, in a building to be erected for the purpose, by consent Glucose ..
of the Colonial Government. It will include manufacGum (with a trace of acid)..
Org. matter- tures of all kinds. The date fixed for the opening is 2.98
Sol. in water Albuminoid matter
4:63 February 15, and everything intended for the Exhibition Pectose..
must be shipped from London not later than during the 77-27| Org. matterCellulose
3'76) Insol. in water 81'03 should communicate immediately with Mr. Edmund
first week in December, 1876. Intending exhibitors Mineral matter, sol. in water
'insol.in water 3:58} Ash 3.64 Johnson, Commissaire Délégué, at the European Central Water ”..
Offices of the Exhibition, 3, Castle Street, Holborn, 10'70 London. The Exhibition will be arranged in the follow
ing classes :-Class 1.--Alimentation. Class 2.-Che
micals, perfumery, medicines, and surgical appliances. These figures, especially if taken in connection with Mr. Class 3.-Furniture. Class 4.–Fabrics, clothing, watches, R. T. Brown's results, are strongly suggestive of the jewellery, ornaments, precious stones. Class 5:-Means
of transport, travelling equipments, harness, saddlery, &c. occasionally eaten by the negroes of the Southern States, but the sub- Class 6.-Hardware, edge tools, cutlery, metal work of all stance can by no means be said to be common, or commonly used as kinds. Class 7:—Machinery, materials, and construction. an article of food. In the analysis there is obviously a little error of statement in reporting elementary nitrogen and accounting for all Class 8.- Agricultural, &c. Class 9.-Science and that remains of ioo per cent in non-nitrogenous material.
Education. Class 10.-Miscellaneous.
Dedue o equiv. to} 0-163
20, 1876. THE HYGIENIC CONGRESS AT BRUSSELS. M. VARRRENTRAP pronounced against all waters obtained
from the towns themselves. The inauguration meeting of the Congrès International M. T’SERSTEVENS insisted that water ought to be d'Hygiène et de Sauvetage took place at the Palais des obtained from places thinly populated; where the soil is Académies on the 27th ult., His Majesty the King of the barren and the water superabundant. Belgians being present. Lieut.-General Renard welcomed M. Delve advocated the periodical inspection of cisterns. the Foreign Members of the Congress. M. Vervoot then The papers on the sewage question included one by delivered his Inaugural Address.
Mr. Crookes, who described the A B C process of purifyThe Congress was divided into three sections, viz.- ing and utilising sewage. Hygiene, Saving of Life, Social Economy. The English M. L. Derote, Engineer of Bridges and Roads, on the
The programme of the conferences included a paper by Committee was constituted as follows:President.--Capt. Douglas Galton, C.B., F.R.S.
conclusions of the report of the English Rivers Pollution Hygiene.—Presidents, Mr. Edwin Chadwick, C.B., Commissioners, so far as it concerns the oxygenation of and Dr. Richardson, F.R.S., &c; Vice-Presidents, Dr. contaminated waters; and on the purification of the Senne Hardwicke and Mr. H. H. Collins; Secretaries, Mr. J. S., and the drainage works of the town of Brussels executed Phené and Mr. J. W. Pearse.
under his (M. Derote's) direction. Saving of Life.-Presidents, Sir Henry Verney, Bart.,
Full reports on each subject brought before the Congress and Mr. William Crookes, F.R.S., &c.; Vice-Presidents,
are being prepared, and will shortly be printed. Surgeon-Major Pater and Mr. G. M. Cooke ; Secretary,
The King of the Belgians has offered a prize of Major Burgess.
5000 francs to that city, local authority, or private Social Economy.-President, Mr. John Siltzer; Vice- association which shall, by improvements in the dwellings President, Mr. Willis Bund; Secretary, Mr. John Russell, of the working classes effect the greatest reduction of the M.B.
death rate at the lowest cost. The prize will be awarded The questions discussed in the first section included the
at the next International Hygienic Congress, which will following :-“What are the advantages of the distribution probably be held in 1878. of population ? Discuss the inconveniences which result of water, and what are the means for conveying it to the centres from taking water from the hydrographic basin. Statethe normal consumption per head of the inhabitants."
NOTICES OF BOOKS. “ Which is the most practicable system for ridding a town of its fæcal and putrescible matter and of its mud ? Indicate the means (a) to purify sewage ; (b) to utilise Annual Report of T. P. Fanes, Commissioner of Agricul. the drainage ; (c) to prevent the contamination of water- ture of the State of Georgia for the Year 1875. courses by the refuse from factories; (d) to neutralise the This issue contains a judicious and temperate reply to noxious effects of dung-heaps in the proximity of dwellings, the sweeping objections often raised against the analysis and to determine the circumstances which should regulate of soils as of little value in pointing out their properties. the choice of disinfectants and antiseptics."
We should scarcely, however, give in our adhesion to the In the second section the fifth question was—". What view that fluorine, small as are the proportions in which are the means of preventing explosions and flooding in it occurs, is of no value. mines, and of lessening their effects ? Indicate the most A curious instance is given of a soil which appears to secure means of lighting mines.”
have been cropped continuously for about ninety years In the third section the first question was—" Determine without ever having been manured. The subsoil was the best arrangements, from a moral and hygienic point of originally very rich in plant-food, but its valuable ingreview, for private dwelling-houses. Describe and examine dients have been greatly reduced in quantity. the situation; the methods of heating, ventilation, and The cultivation of cotton is considered very unremunelighting; the means of supplying drinking-water and water rative, and farmers are recommended to turn their attenfor domestic uses; the systems of drainage."
tion, in preference, to wool-growing. There is, however, A report on water-supply was read by M. Zimmer.
a difficulty in the way: 15 per cent of all the sheep in In the discussion which followed the report M. GÉRARDIN the State are destroyed by dogs, which in the United contended that water was good if animals could live in it; States are a greater nuisance than even in Europe. that the higher the organisation of the animal life the purer The Report generally may be pronounced full of valuwould be the water. He did not consider the quantity of able matter, but by far the greater portion of this is of an mineral salts had much influence, whilst the presence of economical rather than of a chemical character. organic matter was fatal to the infusoria. Water from different sources ought not to be mixed.
M. VANDENSCHRIEK believed that 200 litres per diem for each individual was an unnecessary quantity. For. Sydney City and Suburban Sewage and Health Board : merly, only 20 litres were allowed per head, and yet epi
Seventh, Eighth, and Ninth Progress Report of the demics were not so numerous nor so fatal at that epoch
Board appointed on April 12th, 1875, to inquire into and as in the present day.
report as to the best means of disposing of the Sewage M. BERGÉ pointed out (1) that the town of Brussels had
of the City of Sydney and its Suburbs. Sydney: Thos.
Richards. a water-supply dating from Joseph II. (2) That it had been proved that organic matters only are hurtful; that it Wherever mankind congregate in great numbers the was known that water charged with lime and with chloride sewage question, sooner or later, forces itself upon their of calcium killed the fish; that chemical analysis was attention. Believers in laissez faire may for a short time necessary to determine the quality of water. (3) That it shut their eyes to polluted streams, and affect not to perwas not yet proved that the mixing of two good waters ceive the evil odours that hover around them. But in the was injurious.
long run erysipelas, typhoid fever, diarrhea, and perhaps With regard to the distribution of water, Captain cholera, speak in a language which cannot be misunderDouglas GALTON was in favour of constant supply with stood, and action is taken, but frequently when too late. out cisterns in preference to the intermitter:t supply by Rising communities, whether in the British colonies or in cisterns.
the United States, cannot too early set about combatting The Count TORELLI thought the determination of the the inevitable cvil. The longer the needful measures are quantity of water per head to each inhabitant very difficult, delayed, the costlier and the less efficient they will prove. and varied naturally with the climate and the various con- Australia has hitherto enjoyed a remarkable immunity ditions of the population.
from zymotic diseases, but if fever is once introduced
171 Oct. 20, 1876. its complete expulsion may not prove easy. The Sydney , structions. In treating of cochineal and indigo no alluauthorities do not seem favourably disposed towards irri- sion is made to the specific gravity of the samples, the gation. It must be admitted, on the one hand, that in so determination of which is an easy and rapid way of decomparatively dry a climate as that of Australia this tecting mineral impurities, whether accidental or intenmethod of dealing with sewage seems more feasible, from tional. Light cochineals and indigos may certainly be an economical point of view, than under the cloudy and bad, but heavy ones cannot be good. Flavin appears to drizzling skies of England; but, on the other hand, the have been entirely overlooked, and the extracts of the dye. danger to health will undoubtedly rise with the average woods are spoken of merely in the solid state in which temperature. We scarcely understand the precipitation they are so often met with on the Continent, and not in scheme recommended at Sydney. The material to be the liquid form prevalent in England. The preparation of employed is the carbonaceous residue from certain shales extracts, we may here observe, is one of the branches of employed in the manufacture of kerosene oil. We can manufacturing chemistry in which England is now not readily see how this matter might form a useful filter-bed, holding her own. Very considerable quantities both of or how it might be employed as an adjunct in a precipita- French and American extracts are now used in Lancation process; but we are not aware that it contains any shire. principle capable of acting as a true precipitant.
The tables showing the reactions of colouring.matters
-natural, artificial, and when fixed upon textile fibresPractical Manual of Chemical Analysis and Research authors have in many instances taken the useful precau.
are very complete. As regards the coal-tar colours, the applied to the Arts and Manufactures.". By P. A. tion of giving the name of the manufacturer, often the Bolley and E. Kopp. Second French Edition, revised only method of identifying the exact substance in question. and enlarged. Translated from the Fourth German
The least satisfactory portion of the work is the se&ion Edition, by Dr. L. GAUTIER. Parts 3 and 4. Paris : on milk, which is altogether out of date, and in which F. Savy.
much space is devoted to those deplorable instruments This Manual is more extensive in its scope than any the lactometer and the creamometer. similar work in the English language. With the excep- The book will form a useful addition to the library of tion of purely pharmaceutical products it embraces every reference of the analytical chemist. class of substances which are likely to fall into the hands of the commercial analyst or the “works-chemist.” But as the entire book does not greatly exceed one thousand pages, we need not be surprised if some bodies are dis
CORRESPONDENCE. posed of rather briefly, whilst others are treated at a disproportionate length. Thus alcoholic liquids occupy nearly one hundred pages, whilst soils and manures
ROSE COLOUR OBSERVED IN THE which in this country certainly occupy a much larger share of the atiention of analytical chemists-take up MANUFACTURE OF CHLORATE OF POTASH. merely forty-two. In treating of the determination of phosphoric acid in manures and phosphatic minerals, the
To the Editor of the Chemical News. authors declare their conviction that of all known methods Sir,– The following facts may throw some light upon the the molybdic acid process alone is capable of a general origin of the “ rose or red-violet colour observed in the application, and yields results really trustworthy. All the other methods described, gravimetric or volumetric, are in Dr. Hofmann's “Report” &c. (Chem. News, vol. xxxiv.,
course of manufacture of chlorate of potash, as noticed inexact or very tedious, on account of the presence of iron
p. 139). Nearly all commercial samples of chloride of ör alumina. The authors decide, contrary to the view of lime give, when boiled with distilled water, a splendid Birnbaum and Chojnacki, that nitric acid cannot be safely violet-red solution ; on filtering through paper the colour used as a solvent in the analysis of mineral phosphates, as disappears, and the paper is stained brown : if it be renotable quantities of phosphoric acid remain undissolved moved from the funnel, washed from adhering chloride of in the residue. They recommend hydrochloric acid when lime, and moistened with pure strong hydrochloric acid, the presence of iron in the solution can occasion no diffi- the stain disappears, and a yellow solution is formed, culty, as when the molybdic method is to be used; In which gives the characteristic iron-rea&ions with ferroother cases Graham's solvent-sulphuric acid diluted cyanide and sulphocyanide of potassium.
The purple down to 5 per cent of the monohydrate—may be advan- solution may be obtained clear” by subsidence, and may tageously employed.
then be drawn off with a pipette; it may be evaporated For determining "reverted” phosphoric acid in manures nearly to dryness on the water-bath without decomposithey prefer the indirect method—ascertaining the total tion, but on applying a somewhat stronger heat, to drive phosphoric acid insoluble in water, and dedu&ing from off the last traces of moisture, the coloured compound is this quantity the phosphoric acid insoluble in citrate of decomposed, and the mass acquires a browu tinge. ammonia.
If alcohol be added to the clear coloured solution a blue In treating on aræometry the authors strongly recom
shade is first developed, and afterwards the colour gramend Twaddle's hydrometer, in preference to those of dually fades into a faint brown. Baumé and Beck, so much employed upon the Continent, To determine the question of the presence of mangaand which are as devoid of any rational foundation as is nese, one drop of the coloured solution was placed on the English system of weights and measures. In the examination of magenta for sugar--an occasional bath ; a brown stain appeared where the liquid had been :
white filtering-paper, which was then dried on the wateradulteration—it is recommended to withdraw the colouring this was cut out, and divided
into two parts; one of them matter from the solution by means of wool or silk, or to
was moistened with hydrochloric acid, and drops of ferro. precipitate it with common salt. The sugar then remains cyanide and sulphocyanide of potassium placed on oppo. in solution, and may be easily recognised, and, if needful, site sides of the moistened portion ; strong iron reactions determined.
were obtained in each case. The directions for the examination of lac-dye are some
The other portion of the stained paper was incinerated what insufficient. For certain uses, as in dyeing stuffs and fused on platinum-foil with a little carbonate of soda; which require to be hot-pressed, it is very important that lac-dye should contain a minimum of gum-lac, for the with this most delicate test,
no trace of the manganese reađion could be observed approximate estimation of which the authors give no in
It is evident, therefore, that in the case in question the * Manuel Pratique d'Essais et de Recherches Chimiques appli- colour of the solution of chloride of lime is due to iron, qués aux Arts et a l'Industrie."
not to manganese, and it would seem most probable that