Imatges de pàgina
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NEWS

ADDRESS TO OUR READERS.

basis, and has for its sole object the promotion of know

ledge. On commencing a new year and a new volume, we may In conclusion, we may add that it is our intention to be excused for printing once more a short statement of publish occasional courses of lectures, and popular our aims and objects. The CHEMICAL News was papers, on different branches of the science; and it is to started four years ago, with the purpose of supplying be hoped that our more recondite readers will look with the chemist with the earliest information on the results favour on these attempts to diffuse more generally a of laboratory investigations in pure science ; the knowledge of chemistry, and so, we hope, stimulate a technical chemist with the practical applications of the desire for a more profound acquaintance. science to his various occupations; and the medical profession and pharmaceutists with every novelty of interest

SCIENTIFIC AND ANALYTICAL relating to the materia medica, toxicology, and phar

CHEMISTRY. macy. These are the objects we shall still keep in view, and steadily pursue. All the information of importance we can collect from European and American sources will

Contributions to the History of Thallium, be regularly supplied; original researches, and articles

by WILLIAM CROOKES, F.R.S. on matters which may attract particular attention, will Oxalate of Thallium.—This salt is readily prebe frequently published; reports of the proceedings of pared by boiling together equivalent quantities of carsuch scientific societies as possess especial interest to

bonate of thalliam and oxalic acid, in just sufficient the chemist will receive the earliest insertion, and works water to dissolve the product when hot. Upon cooling, relating to chemistry an early notice. Specifications of oxalate of thallium crystallises out in the form of small all patents in applied chemistry will be reviewed as soon prisms, brilliantly white and lustrous. It is not as they are made public. In this way we hope to keep very soluble in water, and is insoluble in alcohol. One our subscribers au courant with the progress of pure hundred parts of boiling water dissolve 9'031 parts of and industrial chemistry all over the world.

the salt; and the same quantity of water at 60° F. In like manner we seek to afford the pharmaceutical

dissolve r'443 parts. One part of the oxalate, therefore, chemist and druggist every information necessary to

requires 11:07 parts of boiling water, and 6927 parts assist him in the practical and scientific prosecution

of cold water to dissolve it. M. Kuhlmann has ascribed of his occupation. Nor are the political interests of the

to the neutral oxalate of thallium the somewhat profession altogether overlooked or neglected. The

improbable formula, C_TIO:; but several closely conCHEMICAL News is the organ of no society, and is, there- |

| cordant analyses have shown me that this salt has fore, free to urge reform wherever it may appear needed,

the normal constitution of neutral oxalates. The and to encourage every effort to promote the general

method adopted for analysis is very simple, and gives interest.

remarkably accurate results. A weighed quantity,

which had been dried over sulphuric acid, was gradually The present year will be fraught with interest to the

heated in an air bath to an increasing temperature, the chemist and druggist. A national Pharmacopæia is

weight being taken from time to time. At 230° F. a about to appear of more important a character than any

trace of hygroscopic moisture was driven off, and the which has issued from the College of Physicians. This

oxalate then bore a temperature of 400° F. without work will receive our earliest attention, Again, the

further change. At 480° F. it began to discolour slightly, rights of chemists and druggists are seriously threatened ; and it will be necessary for the majority to combine in

but it was found to have lost scarcely any appreciable

weight. Pure concentrated hydrochloric acid was afterorder to defeat any attempt of the Medical Council to

wards poured over the crystals ; slight heat was evolved, deprive them of their privileges, as well as to secure the

and in a few minutes they were converted into a porous, exemption from serving on juries, which has already

spongy mass of chloride. The excess of acid was been conceded to a section. To promote these objects

evaporated off over a water bath, and the residue was we shall render every possible aid.

heated to 400° F. for ten minutes. More hydrochloric The thorough organisation of the trade should be com

acid was then poured on, and the evaporation and heating pleted as early as possible, and the machinery is for

were repeated. This was performed until no alteration tunately ready by which this can be effected. The

of weight took place, the final heating being in an air United Society of Chemists and Druggists offers the means

bath at 500° F. As oxalic acid is entirely dissipated by which the entire body may operate in concert. We

| by exposure to a temperature of 320° F., the above say this in no spirit of opposition to the Pharmaceutical treatmeotee

treatment effectuaily zemoves this acid. Many experiSociety. That society voluntarily closed its doors to the ments have satisfied me that chloride of thallium will majority of the trade some years ago, and now can be

bear 'n temperature of 500° F. without any loss of in nowise astonished that, at the present crisis, some

weight; at a;slight increase of heat the chloride sudother organisation should be found necessary.

denly fuges toʻådhu brown liquid, white vapours being But it must never be forgotten that the occupation of simultaneously evolved a chemist and druggist has a scientific as well as a com Analyseg:corducted in the above manner gave the mercial aspect; and we are glad to have the opportunity following percentages of metal in this salt :of recommending to our readers an organisation which

82-298 has for its object “ the encouragement of pharmaceutical

82-274 research.” The British Pharmaceutical Conference offers

82.230 the means by which every one who will interest himself

82'206 in the improvement of pharmacy can be brought into communication with others similarly disposed, so that

Mean 82'252 all may work in concert for the common good. We The formula C,TiO, requires 82.186 per cent. The heartily commend the Conference to the notice of our neutral oxalate of thallium has, therefore, the normal readers. It has been organised on a thoroughly catholic composition. It contains no water of crystallisation.

Vol. IX. No. 213. JANUARY 2, 1864.

Binoxalate of Thallium.-Upon mixing together was deduced, which agrees with the number obtained two equivalents of oxalic acid to one of carbonate of by Johnson and Allen, viz., 133'03, and fully authorises thallium, and boiling, the binoxalate is deposited, on the use of the round number, 133, as expressing the cooling, in the form of large plates, having a pearly combining proportional of this element. lustre. The crystals were purified and analysed in the Deliquescence of CsC1.-Bunsen further maintains same way as the neutral oxalate. Upon exposure for the accuracy of his original assertion that CsCl is if hours to a temperature of 270° F., the crystals deliquescent. Johnson and Allent had stated that it became opaque, and were found to have lost 3.61 per was“ not only not deliquescent, but scarcely bygrocent. of water. Further heating did not increase this scopic.” The observations of both are entirely correct loss. The percentage of thallium in this dried salt was for the circumstances under which they were made. found to be 69'341. The formula C HTIO, requires We have since observed pure CsCl to deliquesce in a few 69.520 per cent. of metal.

moments on an August day; while at this writing, The amount of water present in the crystallised bin- September 24, the same specimen has been exposed oxalate did not correspond in my analyses to a definite all night to the air in a room with open windows, number of equivalents. The mean percentage obtained was temperature 55° F., and is in appearance perfectly dry. 3.61. One equivalent of water in the binoxalate would Bunsen rightly remarks that “ Johnson and Allen appear require a loss of 2.99 per cent., whilst two equivalents of to have made their experiments in a comparatively dry water would correspond to 5.80 per cent. The method of atmosphere, in which, as is known, many deliquescent analysis was such as to render the probable error of salts are unaltered, and, therefore, overlooked the demanipulation insignificant; and the closely concordant liquescent character of CsCl.” The experiments of results obtained in the estimating the thallium in the Johnson and Allen were made in the clouds and foggy. dried salt prove that the error was in the amount of but cold weather of November,- weather which is comwater originally possessed by the binoxalate when takenmonly designated as damp, but the real moistness of for analysis. It had been dried for thirty-six hours over the atmosphere they only judged of from sensation. sulphuric acid, and it is not unlikely that it may have CsCl much resembles urea in its hygroscopic relations, slightly effloresced. An estimation of the water of | The latter substance is stated by most recent authors, crystallisation, in a specimen taken out of the mother including those who have had occasion to observe it liquor, and merely dried by pressure between blotting especially, to be unaltered in the air. Thus Lehmann. paper (containing, therefore, a little free moisture), gave “ Physiological Chemistry;" Gorup Besanez, “ Zoocheresults corresponding to a little more than two equiva- mische Analyse ; ” Mitscherlich, "Lehrbuch ;" Gerients of water. I am, therefore, justified in assuming hardt, on authority of Pelouze, “ Traité de Chimie that the formula for the crystallised binoxalate of thal- | Organique ;” and Neubauer, " Analyse des Haras." lium is

assert that it is unchanged by exposure to the air. Gorup C HTIO +2 Aq.

Besanez, “Lehrbuch der Physiologischen Chemie," 1862, It is strongly acid to test paper, and is much more states that it is “ permanent in the air, but rapidly soluble than the neutral oxalate, requiring less than its absorbs moisture.” Gmelin mentions that "according own bulk of boiling water to dissolve it. At 60° F., to earlier statements it deliquesces in moist air.” We 100 parts of water dissolve 5'338 parts of the anhydrous have repeatedly observed that in very moist air urea salt, equivalent to one part of the salt in 18.73 parts of rapidly deliquesces, though usually, except in summer cold water.

weather, it is not visibly affected by atmospheric moisture.

Spectrum of Casium.-Johnson and Allen, in the

paper above referred to, observed that “Kirchhoff and On Cesium.

Bunsen, in the figure given by them (Pogg. Ann.. 1861, Separation from Rubidium.-Bunsen* has made and Fres. Zeitschrift für Analyt. Chemie, Heft 1, 1862), further investigations on this rare element. He could represent eleven lines. We find without difficulty seven not apply Allen's method to the preparation of pure more lines, and observe further that some of those cæsium compounds because of the small quantity of figured by Kirchhoff and Bunsen are not mapped in their the element obtainable from the sources at his command. correct position." Ho discovered thai cæsium could be separated from In relation to this, Bunsen remarks, “ We regret that rubidium by another plan, which is as follows:--In a Messrs. Johnson and Allen appear to have neglected to mixture of pure RbCl and CsCl the Cl is determined, and make an accurate comparison of their spectrum with from its amount that of Rb is calculated. The chlorids ours, otherwise they would have easily convinced themare converted into carbonates, and. 10. the latter.sąlts a selves that the lines given by them agree with ours as little more tartaric acid. is added than is necessar: to closely as is possible; that, on the other hand, three produce neutral tartrate of cæsium and bitartrale: of lines are figured on our plate which do not occur at all rubidium. The mixture dried and pulverised is brought in the cæsium spectrum. These lines have been printed upon a funnel, whose neck is' stoppel:by a small filter, on a number of lithographs by fault of the lithographer, and the whole is placed in an atmosphere saturated with in consequence of a misunderstood proof that was not moisture. The neutral cægium: salt "défiquesces, and sent to us for revision, and lie near and to the right of the passes the filter, while the acid' i'ubidium.sait remains lines designated by Johnson and Allen as VI., X., and XV." behind.

Johnson and Allen could but conclude that the coloured Equivalent.—The cæsium tartrate was converted plate in Poggendorff's Ann., accompanying the paper of into chlorid, and the latter was purified from traces of Kirchhoff and Bunsen, was a copy of their spectrum as KO and LiO, which it acquired from the tartaric acid, far as the important, i.e., the characteristic and brilliant by conversion into platin-chlorid, washing, &c. This lines were concerned. They are therefore scarcely more operation was repeated six times, the salt being each in fault in having " neglected to make an accurate comtime analrsed. The last three results coincided very parison" than Kirchhoff and Bunsen are in permitting closely, and, from their average, the equivalent 132.99 | incorrect spectrum plates to be circulated. Fresenius * Pogg. Ann., cxix., 1.

+ CHEMICAL News, vol. vii., p. 110,

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