장음표시 사용
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limatiqn be asterWatas dissolved in botling Water, and aliomedio crystallige as it cools. Benzora acid has a Strong, pungent, aromatic, peculiar odour. Iis crystals are ductile, not pulverizable; it sublimes in a moderate heat, forming a White, irritating smolae. It is solubio in about 24 times iis Weight of boiling Water, Whicli as it coolsprecipitates Nilis of What it had previolasty dissolve l. It is solubie in athohol. It may be crystallized by solution in botling water, as by dissolving l oz. to ibiss. of Water, and after-Wards allowing the solution to coolor by sublimation; but asin iis crystalline forni it cannot be reduced to powder by mechanical means, it has been somelimes thought bettersuited to the purposes of medicine that it should be hept in that more divided state in Whicti it is precipitated.
Diluted sulphurio Acid nitio fluid
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Wash the Citrato of Lime whicli rema ins hy repented additions os fres h water, and then dryit. Add . the diluted sulphuric Acid to thodried poWder, and boti it for ten minutes; thera press it strongly through a linen cloth, and afterivards filior it through paper. Letthe clear liquor Whicli has passed evap rate in a gentie heat, so that Cry Stais may sorua as it vis colli To render ilicse crystals pure, dissolve thom a se cond and thirii timoin Water, and after ench solution si iter ilis
The generat use of temon juice for the purposes of m dicine, the uia certainty of obtaining it hom the fresti fruit, and the dissiculty of heeping it utichanged, have rendered the
adoption of the prosent forna expedient, is not absolutely necessary; and there are some potnts of practice, as in the exhibition os effervescing draught where the diminished buth of the acid and iis sto ver action as it dissolves Dom a solid state, giveit considerable a luantage. Tliis process owes ita origin to Scheele, and the acid has thus been for some years prep edirpon a large Scale and in a very pure stato by Ain. Coxwellos Fleet-street. It depentis upon the formation os an insolubio citrate of lime, which is asterwards decomposed by the stronger assini ty of sulphuric acid; and the dctached citr acid remains dissolved in the liquor, while the newly-formedinsolubie sulphate of lime precipitates. The liquor Whichcontains the citric acid is evaporatcd untii the acid crystal-
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lietes as it cools ; but hom the action of the sulph ic acidupora so me adherent mucilaginous matter, the Urst crop of crystals will be smali, os a darii brown colour, and impure, and their colouring matter can only be separated by a repetition of the solution and crystalligation tWice, and, is the crystala be not then colourless and weli formed, even a third time. The use of rathen more sulphuric acid than is requisite to the decomposition of the citrato is intonden forthe complete destruction of the mucilages, for Without thisbe effected the acid will not crystallige. This dissiculty of crystalligation has been urged against the preparation ait gether, and a concentraled liquor has by sonae been suggest-ed as more convenient ; probably much of this object ion illia removed by practice, for that an elegant and pure articio may be prepared upon a large scale, the great supply WhichMr. Coxweli is enabled to malae sum ciently proves. of the Grystallized acid, one ounce dissolved in one pint of Vrater isequat in strength to one pint of common lemon juice. Equalparis of the crystals and subcarbonate of potasti are suffcient for the mutuat saturation os cach. Os couiso, the solution in mater has only the acidity of temon juice, not that flavo urWhicli depends upon the admixture of iis essentiat Oil, and which sor so me purposes may he a usesul addition. Thoc atais are rhomboidal prisms, whose fides incline to cachcther at angies of 12O ' and 6O', terminating at each end by Dur trapezoidat saces Whicli include tho solid angies. Theyare not altered by exposure to air. Water at 2l2R dissolvestwice iis meight, 75 paris of cold watur dissolve l0O paris. It would be advantageous is the citrate of lime could bemade and imported as ureli as the fruit iiseis; for the great perfection of the lemons in warmer climates,i the quantity Ofacid theyyield, and the smali comparative space Whicli the Prepared sali Would occupy, would nil tend to diministi iis present price very considerably. It may be and has been attempt-
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od to substitute sor it the cheaper tartarous acid, hut this maybo detected is to a solution of the lalter a solution os tartrate os potash be added, for an insolubie supertartrate os potashwill then be formed and precipitate in granular crystals. This preparation properly made, o es notae of iis acidi ty to adherent sulphuric acid ; is it does, the precipitate 3 iel ded by asmali addition Os solution os acetate os lead; will, as sulphaleos lead, be insolubie in acetic acid, While citrate os lead willbe entired solubie in the Same menstruum. It may farther be observed, that although the process herexiven usili commonly ansWer, yet, that as temon juice some- times varios in the proportion of acid it contains, it may occasionalty require so me modification of the quantity of sulphuric acid to be added. Proust states Iourn. Phys. 52. that 7q. paris of citrate of lime require 20 paris of sulphuricacid os a sp. gr. I, l5 for this Purpose.
Acidum Muriaticum, P. L. 178I. Spiritus Salis marini Glauberi, P. L. 1765. Spiritus Salis, P. L. I 20.
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Md the Muriate of Soda; pour the rema inder of the Water into a receiver, aud, haVingluted it to the rctori, disti l the muriatic acidinio it by the heat os a sanit buth gradu ally
The specific gravi ty of muriatio ac id is tolliat of Water as I, I7o to I ooo, and a liuidounce diluted With Water ought to dissolve of a lum p of lime-stone immersed therein,
This process differs froin the former in many practica1poinis. The proportion os sulphuric acid requisite for thecomplete decomposition of the sali is as 3 to 4, and as thelast portions os muriatic acid adhere more strongly, so dothey require sor their delachment that the temperature inould be considerably increase l. Is sulphuriC acid, undi-luted, be added to muriate of soda, there is an immediate andvnmanage te extrication os muriatic acid gas, and to preventiliis, a dilution of the sulphuric acid with - of water, allowingsuch mixture to remalia illi iis increased temperature be sunEto the common standard, is previousty directed. Is the wholecharge of acid, mater and salt be introduced into the retori, the firsi subsequent application of heat delaches muriatic acidgas Without a suffcient quantity os mater to condense it, and a portion in this Way passes to Naste. By introducing some of the water into the receiver this gas is condensed, and the produci is in the fame proportion stronger. For the condensation of the whole muriatic acie gas a certain quanti of Water is necessary, and, in addition to that Whichis hero directed to be used, the quantity also contained in the
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an attached botile containing the water, or any modificationos Woulsela apparatus, may be used at the pleasure or conVenience of the operator, but such is not directed in the Pharmacopoeia, because a common retori and receiver are sussitient, is care be taken not to lute them closely untii ali thecommon air be sirst inpelled. By the previous dilution of the sulphuric acid the charge Will be hept in a quiescent stata untii the application of heat be made, and thus time willhe given to the operator for the adaptation of the receiver. The addition of the sest to the acid is also os importance, because it prevenis the chance of any subsequent accident to the retort. The charge should not occupy morethan half the body of the retori, and as it is of importanceto preserve the Vesset, it may be proper to ades, that this may perhaps best be done When iis contenis have coolen to absutili 2 by pouring in sussicient Water at the fame temperatureto fili it. The residue is sulphate of soda, with a superabundance of sulphuric acid, and is farther to be prepared according to the directions givon for that sali. The specificgravity may be thought to be placed too low, but it is theresult os severat triais, and cannot be hept higher under theusual circumstances of temperature. It is colouri ess, or
phuric acid it may be discovered by ruriate of barytes, and puris eu thereisom, is such purification bo thought necessary, by a secoud distillation sum a s mali quantity os
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Mix thom in a glass retori, then distit theni tric acid in a sand bath, untii a red vapourarises: lastly, having ad ted to the acid sirgidistilled an ounce more os dry nitrate os potasti, distit the nitric acid again in a similar
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heretofore varied much in the proportions they have directed, and Frederic Hossinari used equat paris of the sali and acid. Tho increase has been made chiesy with a vieW to obtain thenitric acid as Dee as possibi e Dom nitrous gas ; and when this arises, whicli is discoverable by the red colour it imparis to the acid, the process is to be stopped. The quantity of acidthus obtained is greater in iis value than where half the weight only of sulphuric acid is used; iis colour is also much pater, and it is theresere better nitric acid, but it has been considered as tess pure because it is more likely to contain sulphuric acid; and on this account a second distillationfrom a Desii portion os nitre is directed. The nitric acid is commonly prepared by heating the coloured acid untii the red
a process not only nitrous gas but a large proportion of the acid itself passes io Waste. Is any sulphuric acid be present, nitrate os silver Will discover it, and is added in sufficient quantity, Will also remove it; but after the seconci distillationsuch an impurity is not to be expected. A tubulated receiverand attached vesset, hept cold by immersion in Water or ice, or Woulla's apparatus may be used. Nitric acid, is pure, is transparent and colourless, but it is
more commonly Orange-coloured, Dona the presence of nitrous gas. In the former state of these it emits White fumes, in the lalter orange-coloured ones: it tinges the cuticle ofa permanent yelloW colour, and is suffciently long applied
corrodes the si in iiself as a caustic. The specific gravityis stated to be 1,5O0, whicli is loWer than some authors havegi ven it. The Pharm. Edin. mahes it l,550, and Mr. Κirwanat 60', i,554 3, and at this he considers I 00 pis to contain 73, 54 of real acid Dee Dorn water. The reason for the adoption of these proportions sor
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nitric acid, is expressed in the folloWing repori made to the College.
When the proportions Uere 6 nitre and 3 sulphuric acidthere remained no redundant acid.
Adidum nitrosum dilutum, P. L. I 787.
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aridum vitristicum dilutum, P. L. I 87. Spiritus vitrioli tenuis, P. L. II45.