The pharmacopoeia of the Royal College of Physicians of London, MDCCCIX

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Pharmacopoeia Londinensis, The London PharmaCOPmin.

severat Weights are denoted.

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The mensures of liquid S also disser, oneheing used for beer, and another sor Wine: ve adopi the lalter, and employ for liquids, mensures vllicli are derived frona the wino gallon. The wine gallon is defined by the statutes of tho reaim, and we divide it for medicat pur- poses in the solio Ving mannor, ViZ.

The gallon Cong. The pini The fluidounce The fluidrachm

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mensure the smaller dis istons os liquius bya glass measure marheu at equat distances : forthe number os drops is a fallacio us and tincer-faan mode of dioision since compared mith thosere mater, ulmost double the number os drops

of any tincture are required to fit the fame

suration of liquids and the division of the wine pini, bywhicli it is intended to introduce accuracy in the meaSUrementos quantities of liquids below one drachm. For these thetable of no former Pharmacopoeia has provided, but as Some Such were alWays absolutely necessary in datly practice, so theuncertain method os drops was adopted, and has been gener- atly received. The number os drops contained in one flui- drachm has been assumed to be fixty ; and taking mater as astandard, this number, though by no means accurate, Would stili be sussiciently correct for ordinary purposes; but Whenother liquids of less specific gravity are Used, a much largernumber is required to sill the fame measure: thus of proos spirit I4O drops are required to equat the bulla os fixty of Water dropped Dom the fame vesset. Ιs, theresere, in thecomposition os medicines, measures suiled to the standard of Water Were used occasionalθ only, and it Was generalty assumed that fixty drops were equat to one fluidrachm, and One

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drops prescribed, tWice the do se intended Would he given. It mav be further objected to the use of drops; that their bulla is influenced by the quantity of liquid contained in thebotile Dorn whicli they fati, by the thicla ness of the lip, andoven by in equalities in the different paris of the lip of the same botile; that volatile liquids, to Whicli this mode is most

commonly applied, are thus exposed mitti extensive sursaces and their evaporation promoted; and on every account the adoption of so me deciSive, convenient, and uniform substitute became necessary. The subdivisions of the wine piritare there re extended to the si xii eth part of the mil- drachm, and glasS meas ures e X pressive of sucti subdivisionsare adopted by the College. Γhese Will be as uniform and constant as the weighis employed for solids ; the accuracyof the former as weli as of the lalter being, of Course, dependent upon precision in their construction, whicli is not more dissiculi to be attained in one than in the other instance. Similar Latin term s and characters have been here tofore Used to express the weights of solids and the measures of liquids, and thus very different quantities have, in faci, been expreSSed by the fame name ; an error Which became more evident

when it Was propos ed to extend it stili farther, and to cali thel east division os liquids by the name of a grain. This similarity has been a fource of complaint froin the time os Galen De compos. Medicam. l. 6, 98), and, on adopting more minute divisions os liquids, the College resolved also to aSSUme certain arbitrary terms Which may distinguisti belWeenthem and the weights of solids ; and in thos e talaen, theyhave, Willi respect to measures of ounce and drachm, Whichare in mOSt Common use, been anxious to do as litile violence as possibie to establis hed habiis, consistent Nith thedistinction at whicti they have almed -, and whicii they have also upon the fame principies extended to the sigris by Which

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Such measiares may be designate i. In our oWn langu age theterna sint is sufficient ly distinct frona found, and may stillbe retained as a translation os octarius. In the banishment however of a particular practice frona pharmacy, the banishment of the term immediat ely expressing it, and forcing it Upon the recollection, became also necessary ; Dr this reason the word dros could not be retained to signi se the fixtieth pari os a fluidi aelim, and the coinage of a new one has been

The College have adopted the glass measures originalty invented by the late Alr. Timothy Lane. F. R. S. in Whichthe standard wine gallon of the Exche quer is dividedinto 6l,44O paris, noW called minims, and whicli are applicabie with accuracy to the mensuration of the smallest of these quantities. By an act of parti ament, io Aran, the Wine gallon is si Xed at 2S 1 cubic inches, and the weight of the standard excite quer gallon of water at a temperature Os 639, and barometrical pressure α 29, 52, is 58, II 6 Troy gratias. It wili fur ther be remembered, that the USe of measUres orWeighis made by any particular person is not insisted upon; and provided they be accurate, it is of no importance whereor hoW they are Procured. Perhaps sufficient attention is scarcely paid in generat tothe state os scales and weighis: they are necessarily eXposed, in the shop of the Apothecary, to circumstances Under whichtheir accuracy is impatred, and they require greater careon this account. The beam should rem ain in equilibrio evenis the scales be changed, and it should turn with a very smalladdition to iis weight ; the foris used in the Stiops may easilybe procured so nice as to be influenced by Y5th of a grain. I had intended to su sin to this translation a table of the relative value os drops and measure, but I found the formerso very Variabie, that it could not be applicabie under any al-

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Caro is to he talien that Deither coppernor lead enter in to the composition of the

are glaged by lead ure improper.

This injunction is repeated Dom the sormer Pharmacopoeia, and extended stili farther to a prohibition of those vesaeis whose sursaces are CoVered With a glage of lead. In many instances the reduction os substances to poWder requires mortars to be Used os large sige, and suffcient strengili tobear the application os considerable force; these were formerly made of the composition called beli metal, whicli stillheep their place, though improperly, in many shOPS ; mor- tars of iron ought to be substituted for them. In the present system, hOWeVer, the reduction os substances to powder is 8 See a tis ui enu, entit L Remarks on the Daccuracy and

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Dnly Occasionalty practised by the apothecary ; this is most commoraly done upon the large scale by drug-milis in thefrst instance, and the article is thus supplied to the shops in thestate of powder fitted at orace for use. Now this is oneos the modern facilities and arrangements of trade Whichcannot be too cautioiasty looked after. The proprietor of the milis, perhaps, retiarns for a given weight of the grossarticie four-fifths, taking the difference for the use of his machin ery and the necessary loss in preparation. Ηe has also the power of substituting or mixing in an inserior articlemithout much fear of detection, since when those e X ternalqualities, by whicli the goodness of drugs is chi est y estimated, are tost, it is very dissiculi in deed, is not impossibie, to identi' them. Any man who occasionalty loohs at the drugsales of the metropolis, will find very large proportions os

refuse articles whicli ought to be destroyed; these, neVer-theless, sind purchasers, and under the conveniences Whichthe forin os powder gives, are osten dealt out to the consumer, blended in a masterly manner, under the character Osdrugs of superior quality. . It is there re destrable that the Apothecary should powder his own drugs ; and a large ironmortar, Or What is stili beller, a smali hand-mill will effectthis in a sussicient degrest for the consumption of any ordinary concern, eXcepting in a feW articles, whicli are harder, and there re more dissicultly brohen doWn. Where Substances are insolubie in Water, the addition ofWater So as to forna them into a paste may be usefully made, With whicli they are to be rubbed or levigat ed in a mortartill of sussicient sinen ess; this prevenis loss and inconVenien eisOm quantities of the finer powdor being scattered about indust. The mode of separation os powders of sucti substances of an equat degree of sinen ess will be spoken of hereaster. VeSSeis for evaporation, or any preparation os liquids Or

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Wedgwood's Ware, though practicatly no injury arises in the preparation of extracis Dom the Use of tin evaporators hept lean for the purpose, and in their application suci, will boosten found to be most eSpecialty Convenient. Measures should be of glass, or is they be required sor large quantities, of earthen-ware, and by no means os peWter or any metallic composition.

Pro parations of the acid S, aikalieS, Cartiis, Or metuis, and also salts of every kinii, ought

IVO mensure degrees of temperature bys ahren heit's thermo meter, and When we direct

denotes a temperature het ween 9O' and 10O'.

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-- - 32 which gives the corresponding degree of Fanren- heit. The centigrade thermometer of the French, lihethat of Celsius used in Sweden, divides the fame space into 100 degrees, so that I 8O F α 1OO C, and 9 F m 5 C, and to

reduce the degrees to those of F, we haVe -- 32, that is, multiply the degree in both instances by 9, and divide by 4 for the former, by 5 for the lalter, and to the quotientadd 32, whicli Will give the corresponding degree of Fahren heit. or the converse of these operations Wili convert Fali-renheit's degrees into corresponding ones of either of the

other scales.

I Wo definitions of temperature are also assumed Withsuffcient accuracy sor practical use, and it Would be a very destrable thing is we could more approximate to precision, in describing or regulating the higher degre es of heat produced by naked stres, Upon the uniformity of whichthe poWers of Some of the most active medicines considerably depend. This may be imperfectly done by attending to the form and Sige of the furnace, to the quantityos air admitted, to the fige and nature of the mel employed, and to the mutuat relations of these to each other; und, aboveati, by practical experience in their management: but thereis no instrument at present in use that can be satisfactorilyand conveniently applied to this purpose.

When ive speak of Specific Gravity, We SUPPOSe the SubstanCe mentioned to be of the temperature of 55