Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 176

A prescription generally contains several medicinal substances, which are distinguished by medical writers by names indicative of the office which each of them performs. These are--1. The BASIS, which is the princ.i.p.al or most active ingredient;--2. The ADJUVANT, or that which is intended to promote the action of the base;--3. The CORRECTIVE, intended to correct, modify, or control its action, or to cover its odour or taste, as when we add carminatives or diaph.o.r.etics to cathartics, or aromatics or liquorice to nauseous substances;--4. The EXCIPIENT, or that which gives the whole a commodious or agreeable form, and which, consequently, gives the prescription its peculiar character, as that of draught, mixture, pills, &c. To these, certain Continental writers add a 5th, the INTERMEDIUM, which is the substance employed to unite remedies which are not, by themselves, miscible with each other, or with the excipient. Of this character are the yolk of egg and mucilage, employed in the preparation of emulsions.

The medicinal substances, with the quant.i.ties to be taken, generally arranged as above, are said to form the 'inscription,'--the directions as to their combination or dispensing, which usually comes next, the 'subscription,' and--the orders for the exhibition of the compound medicine, which follow these, the 'instructions.' These distinctions are, however, in many cases more technical than useful.

In choosing the form of a prescription it should be recollected that solutions and emulsions generally act with more certainty and rapidity than powders diffused through water; and these, again, than the semi-solid and solid forms of medicine, represented by electuaries, boluses, and pills. On these matters, however, the taste and wishes of the patient should not be disregarded. For this purpose the taste of nauseous medicines should be disguised as much as possible by the judicious selection of an appropriate corrective or excipient. Thus, the disagreeable flavour of Epsom salt may be in a great measure covered by dissolving it in peppermint water; that of aloes by liquorice; that of castor oil and copaiba by orange peel; and that of powdered bark by mixing it with milk immediately before taking it; whilst the bitterness of all bitter substances is concealed by strong coffee.

In order that a prescription may be well made it is not necessary to unite all the elements above referred to. The basis and the excipient are the only two which are absolutely necessary, since there are many medicines which have no need of an adjuvant. The agreeable flavour and odour of some, and the mild and harmless nature of others, often render the intervention of a corrigent unnecessary when they are employed. A single substance may also "be capable of answering two or more purposes. Thus, the adjuvant may also act as a corrigent, as when the addition of soap to aloes, or to extract of jalap, lessens their griping properties, and at the same time promotes their action. In the same way neutral salts correct the colic which follows the use of resinous purgatives, and accelerate their action." According to Gaubius, the number of ingredients in a prescription should scarcely ever exceed three or four. See DOSE, MEDICINES, INCOMPATIBLES, PILLS, &c.

=PRESCRIP'TIONS.= Recipes or formulae for the preparation and exhibition of medicines intended, generally, for immediate use. See PRESCRIBING (_above_).

=PRESERVES'.= A general term, under which are included the various fruits and vegetables which are seasoned and kept in sugar or syrup, more especially those which are so preserved whole or in slices. See CANDYING, JAM, MARMALADE, &c.

=PRESS (Correcting for the).= See PROOFS.

=PRESSURE, BAROMETRIC, on the Phenomena of Life.= M. Bert has contributed to the 'Comptes Rendus'[122] (lxxiii, 213, 503; lxxiv, 617; lxxv, 29, 88) an account of the following experimental researches on the influence of changes in the Barometric Pressure on the Phenomena of Life:--

[Footnote 122: 'Journal Chemical Society,' vol. xxv.]

He finds that at pressures under 18 centimetres of mercury animals die from want of oxygen; at a pressure of one to two atmospheres, from want of oxygen and presence of carbonic acid; at 2-6 atmospheres, from the presence of carbonic acid alone; at 6-15 atmospheres, from the presence of carbonic acid and of excess of oxygen; and at 15-25 atmospheres, from the poisonous action of oxygen alone.

Animals die from want of oxygen when the amount contained in their arterial blood is not sufficient to balance a pressure of 35 per cent. of oxygen in the atmosphere. They die from poisoning by carbonic anhydride when the amount contained in their venous blood is sufficient to balance a pressure of 26 to 28 per cent. of carbonic anhydride in the atmosphere in the case of sparrows, of 28 to 30 for mammals, and of 15 or 16 for reptiles.

As the pressure of oxygen in the surrounding air depends on two factors, the percentage proportion and the barometric pressure, the barometric pressure may be reduced to 6 centimetres for sparrows, if the proportion of oxygen in the air is increased; and it may be raised to 23 atmospheres without causing death, if the proportion of oxygen is reduced by mixing the air with nitrogen. Aeronauts might, therefore, ascend higher than it has. .h.i.therto been possible to do by taking with them a bag of oxygen to inhale; and the danger that threatens divers of being poisoned by the oxygen in the compressed air might be averted by using a mixture of air and nitrogen.

From an examination of the gases in the blood of animals confined in rarefied air the author finds that both the oxygen and the carbonic anhydride in the blood diminish. The dyspna which is felt in ascending mountains is therefore due to want of oxygen in the blood. The diminution in oxygen becomes diminished at 20 centimetres pressure, yet this is the pressure under which the inhabitants of the elevated Mexican plateau of Anahuac live. The oxygen diminishes more quickly and more regularly than the carbonic anhydride. Although there are but very small quant.i.ties of gases simply dissolved in the blood, the chemical combinations in which they take part are dissociated very easily and in a progressive manner under the influence of diminished pressure, and this dissociation takes place more easily in the organisms than in experiments in vacuo.

=PRINCE'S METAL.= One of the names for Dutch gold. (See GOLD, DUTCH.)

=PRINT'ING (Anastatic).= A method of zincography, patented in 1845, having for its object the reproduction of drawings, engravings, and letter-press, from copies however old. To describe briefly the preparation of a plate or cylinder, let us suppose a newspaper about to be reprinted by this means.

The sheet is first moistened with dilute acid and placed between sheets of blotting paper, in order that the superfluous moisture may be absorbed.

The ink resists the acid, which attacks the blanks only. In all cases where the letter-press is of recent date, or not perhaps older than half a year, a few minutes suffice for this purpose. The paper is then carefully placed upon the plate with which the letter-press to be transferred is in immediate contact, and the whole pa.s.sed under a press, on removal from which, and on carefully disengaging the paper, the letters are found in reverse on the plate. A preparation of gum is then applied to the plate by means of a roller, after which the letters receive an addition of ink, which is immediately incorporated with that by which they are already formed. These operations are effected in a few minutes. The surface of the plate round the letters is next bitten in a very slight degree by dilute acid, and on the fresh application of the ink it is rejected by the zinc, and received only by the letters, which are charged with the ink by the common roller used in hand-printing. Each letter comes from the press as clear as if it had been imprinted by type metal; and the copies are fac-similes, which cannot easily be distinguished from the original sheet.

When pen-and-ink drawings are to be reproduced, they are made on any paper free from hairs or filaments, and well-sized. The ink used is a preparation made for the purpose, closely resembling lithographic ink, and may be mixed to any degree of thickness in pure distilled water. It should be used fresh, and slightly warm when a fine effect is to be given. In making or copying a design a pencil may be used; but the marks must be left on the paper, and by no means rubbed with india rubber or bread. It is necessary to add that the paper should be kept quite clean and free from friction, and should not be touched by the fingers, inasmuch as it will retain marks of very slight touches.

Before closing this notice of anastatic printing it may be proper to remark, that the great pretensions originally set up by the patentees have not been fulfilled by its extensive adoption in trade.

=PRINTING (Letterpress).=[123] _Syn._ TYPOGRAPHY. The art of collecting together and arranging movable types for the purpose of printing, in one or more colours, by pressure applied from a flat surface or by means of a cylinder biting the paper to be printed, and which is inserted between itself and the type.

[Footnote 123: The Editor is much indebted to Mr J. E. Adlard for this interesting article.]

In ill.u.s.tration of this section, some specimen types are appended, the greater portion being from the well-known foundry of Messrs V. & J.

Figgins, and should now be carefully read down to render the further remarks intelligible. The key is contained in itself by reading the column as one continuous paragraph with the help of the foot-notes. Some idea may thus be formed of the vast number of distinct kinds of type necessary to carry out the requirements of the present system of printing.

Mention there has been made that the name of the body is determined by its number of lines to a foot; but this must be qualified. The Imperial foot, or inch, or yard, is an arbitrary measure of length in reality as well as in name. When one foundry was sufficient to supply all the types that were required for use in the early ages of printing, then a name and its dimensions could be taken as absolute. But with the increase of printing, type-founders also increased; and this has produced the variations of bodies which are so annoying to the typographer, for one single letter or s.p.a.ce taken from a body larger than its own, yet of the same name, will be enough to throw the column of type out of a straight line all the way through. Still, when we look to the fact that, according to the ancient masters, the large-sized type called _Pica_ (No. 3 and Nos. 18, 19,20 & 21) requires 72-1/2 lines to the foot, and that _Nonpareil_, half its size (No. 9, and Nos. 26, 27, 28 & 29), requires 145 lines to the foot, and recollecting that the slightest variation multiplied 145 times must produce a very sensible deviation, the wonder is that each of the founders should approach each other so closely as they do. An attempt was made some years ago to introduce a certain fixity of standard for each body throughout the trade, based on the French system; the difficulties of altering the standards and matrices of each foundry were seen to be so great that the effort was unavailing.

[Ill.u.s.tration: References to the above types--by reading across.

BODY. BOOKWORK FACE. DISPLAY FACE.

1 Great Primer-- Roman 14 Gt Primer Ma.n.u.script 15 Gt Primer Ext. Ornamented 16 Gt Primer Black 2 English-- Roman 17 Gt Primer Condensed Black 3 Pica-- Roman 18 Pica Antique 19 Pica Clarendon 20 Pica Rustic 4 Small Pica-- Roman 21 Pica Narrow Gauge 5 Long Primer-- Roman 22 Long Primer [Condensed 6 Bourgeois-- Roman [Sansserif 7 Brevier-- Roman 23 Brevier Grotesque 24 Brevier Extended 8 Minion--Rom. & Italic 25 Brevier Open Sansserif 9 Nonpareil-- Roman 26 Nonpareil Egyptian 27 Nonpareil Hair line 28 Nonpareil Ornamented 29 Nonpareil Condensed Grotesque 10 Ruby-- Roman 11 Pearl-- Roman 30 Pearl Clarendon 12 Diamond-- Roman 31 Diamond Grotesque 13 Small Pica 2-line (No. 4 doubled) German Text

During the latter half of the present century there has been a growing disposition to return to the cut of the letters as used by the early printers. To meet this desire, nearly all the type-founders have introduced Old-style faces, but yet modernised as to their peculiarities.

Considering that this article would not be complete without some such notice thereof, as well as to show the contrast, the following is here introduced to the reader.

[Ill.u.s.tration]

These old-faced types cut by the celebrated William Caslon, in or about the years 1716-30, are even now viewed with great satisfaction, and held in high esteem, by judges of the typographic art as master-pieces of shape and finish.

To the list of types presented, and which give a sufficient general view, may be added _Emerald_--between _Minion_ and _Nonpareil_--for book-work, and also for borders and flowers to be used in neat and artistic work; Gem and _Semi-Nonpareil_ for music; and _Minikin_, for music and Oriental work.

The larger sizes of type are, with very few exceptions, simple multiples of the Pica; for instance, 6-_line Roman_ means a roman letter of the depth of six lines of Pica; 20-_line Antique_, an antique of the depth of twenty lines; and so on.

Very little more need be said on the names applied to the different faces.

Letters used in t.i.tle-pages are especially cut for and styled _t.i.tling--Square, Condensed_, and if very much condensed in width, _Compressed_ or _Narrow-Gauge_. On the other hand, when the letters seem pulled out right and left, they are styled _Extended_.

If the reader will notice the type in which this volume is composed, he will observe that the bottoms of the _tail letters_ are very close down upon the tops of the tall letters, and all but touch: this is termed _solid_. When a page or book is required to look light and less wearisome to the vision, the lines of type are removed from each other, and a s.p.a.ce-line inserted between them--the page is now termed _leaded_. These s.p.a.ce-lines used to be cut, by the compositor, from milled lead, first in strips of the necessary width, then of the required length; hence the term _leads_, by which name they are commonly known. However, they were but poor appliances at the best. Moulds are now used for casting the metal to the specified thickness in strips of about 9 inches long, then cut by a machine to a set gauge; by these means the thickness of the s.p.a.ce-lines, or leads is not only more uniformly secured, but far greater regularity obtained in the lengths cut. Here, as in the large type, as above mentioned, Pica is the standard which regulates the lead; in other words, leads are cast as 3 to a pica, that is, 3 leads form the solid measurement of the Pica body; 4-to-pica requires 4 leads, and the body of the lead continues to decrease according to the prefixed figure, which simply denotes into how many parts the pica is to be divided. Leads are cast so delicately fine that 16 form the pica, but they are seldom used. In many of the News offices bra.s.s s.p.a.ce-lines have superseded those cast from type-metal.

The method of manufacturing type is--

The face having been determined upon--light or heavy, round or narrow, as well as the thickness of the downstroke--a piece of prepared soft iron is taken, and upon the tip-end thereof the proposed letter is cut in relief; when this cutting is finished it is case-hardened, and afterwards styled the punch. The strike is the next operation. The punch (the letter cut upon which, by-the-bye, is backward) is now punched, or struck, into an oblong piece of copper, about 3 inches long and 1/3rd of an inch thick, the breadth such as the size of the letter may require: this is the matrix. A most particular part has now to be performed, called justifying; which means that the matrices shall, when placed in the mould, deliver the letters perfectly upright, and all to be true on a line as fine as a razor's edge. When the process of justifying is accomplished, the matrix is fixed at the bottom of a mould, of the shape of a parallelogram, of the size of the body one way, of the width of the letter the other, and the depth the standard height of the type; the molten metal is forced down this tube, either by hand or by a pump worked by hand or steam, the metal filling the matrix (the sunk letter upon which is now forward) receives the shape of the letter, which is once more reversed, or in a backward position, like as the original punch was cut. The castings are released from the mould by a very ingenious method of opening from the two diagonal corners. The types as cast are forwarded on to the dressers to remove burrs and other superfluities; then are placed in long lines in a frame for finis.h.i.+ng; next turned face downwards, and a grooving plane driven across the feet to insure correctness in height; finally looked over for blemishes, when all faulty letters are thrown out; the process is completed by ranging into lines of handy length, and tied up--ready for delivery to the typographer.

=PRINT'ING INK.= _Prep._--_a._ The VARNISH. Linseed or nut oil, 10 or 20 galls., is set over the fire in an iron pot capable of containing fully as much more; when it boils, it is kept stirred with an iron ladle, and, if it does not take fire of itself soon after the smoke begins to rise, it is kindled by means of a piece of burning paper, stuck in the cleft end of a long stick; the pot is shortly afterwards removed from the fire, and the oil is suffered to burn for about half an hour, or until a sample of the varnish cooled upon a palette knife may be drawn into strings of about 1/2 inch long, between the fingers; the flame is now extinguished by the application of a closely fitting tin cover, and, as soon as the froth of the ebullition has subsided, black resin is added, in the proportion of 3/4 lb. to 1 lb. for every quart of oil thus treated; the mixture is next stirred until the resin is dissolved, when dry brown soap, cut into slices, 1-3/4 lbs., is further added (cautiously), and the ingredients are again stirred with the spatula until the whole is united, the pot being once more placed over the fire to promote the combination; when this is effected, the varnish is removed from the heat, and, after a good stirring, is covered over and set aside.

_b._ The INK. Indigo and Prussian blue, of each, in fine powder, 2-1/2 oz.; mineral lampblack (finest), 4 lbs.; vegetable lampblack, 3-1/2 lbs.; stir them gradually into the warm varnish (_a_), and submit the mixture to careful grinding, either in a mill or by means of a slab and muller. On the large scale, steam power is now generally employed for this purpose.

An extemporaneous superfine black ink may be made by the following formula:--Take of balsam of copaiba (pure), 9 oz.; lampblack, 3 oz.; indigo and Prussian blue, of each 1/2 oz.; Indian red, 3/4 oz.; yellow soap (dry), 3 oz.; grind the mixture to an impalpable smoothness by means of a stone and muller. Canada balsam may be subst.i.tuted for balsam of copaiba where the smell of the latter is objectionable, but the ink then dries very quickly.

COLOURED PRINTING INKS are made in a similar way from the following pigments:--Carmine, lakes, vermilion, chrome yellow, red lead, orange red, Indian red, Venetian red, for red; orange chrome, chrome yellow, burnt terra di sienna, gall-stone, Roman ochre, yellow ochre, for orange and yellow; verdigris, Scheele's green, Schweinfurt green, blues, and yellows mixed, for greens; indigo, Prussian blue, Antwerp b., cobalt b., charcoal b., for blue; l.u.s.tre, bronze powders, &c., for metallic colours; and umbia, sepia, &c., for brown.

_Obs._ It is necessary to prepare two kinds of varnish, varying in consistence, from more or less boiling, to be occasionally mixed together as circ.u.mstances may require; that which answers well in hot weather being too thick in cold, and _vice versa_. Large characters also require a thinner ink than small ones. Old linseed oil is preferable to new. Yellow resin soap is preferred for black and dark-coloured inks, and white curd soap for light ones.

A good varnish may be drawn into threads like glue, and is very thick and tenacious. The oil loses from 10% to 14% by the boiling. Mr Savage obtained the large medal of the Society of Arts for his black ink made as above.

A PRINTER'S INK EASILY REMOVED FROM WASTE PAPER. The following process for the preparation of a printer's ink that can be far more readily removed from waste paper than ordinary printer's ink has been patented by Kirscher and Ebner. Iron is dissolved in some acid--sulphuric, hydrochloric, acetic, &c., will answer, and half of the solution is oxidised with nitric acid and added to the other half and the oxide precipitated from the mixture by means of soda or potash. The precipitate is thoroughly washed, and treated with equal parts of solutions of tannic and gallic acids, and the bluish black, or pure black pigment formed, is thoroughly washed and dried, and mixed with linseed-oil varnish, and can then be immediately used for printing from type, copper, wood, steel, or stone. Waste paper printed with it can be bleached by digesting it for 24 hours in a lukewarm bath of pure water, and 10 per cent. of caustic potash or soda, and then grinding it well in the rag engine, and throwing the pulp upon cloth and allowing it to drain. It is then to be washed with pure water, containing 10 per cent. of hydrochloric, acetic, or oxalic acids, or of binoxalate of pota.s.sa, and allowed to digest for 24 hours, and may then be worked up into paper, or it can be dried and used as a subst.i.tute in the manufacture of finer paper.

=PRINTS (Ackerman's Liquor for).= _Prep._ Take of the finest pale glue and white curd soap, of each 4 oz.; boiling water, 3 pints; dissolve, then add of powdered alum, 2 oz. Used to size prints and pictures before colouring them.

=PRINTS, To Bleach.= Simple immersion of the prints in a solution of hypochlorous acid (the article remaining in the solution for a longer or shorter s.p.a.ce, according to the strength of the solution) is generally all that is required to whiten it.

=PRIVIES.= See WATER-CLOSETS.

=PROOF.= See ACETIMETRY, ALCOHOLOMETRY, &c.

=PROOFS (Correcting).= The specimen below, with the notes, will, if carefully perused, put the reader into possession of all the secrets of this useful art.

[Ill.u.s.tration]

[_The same corrected._]

As the _vine_, which has long twined its graceful foliage about the oak, and been lifted by it into suns.h.i.+ne, will, when the hardy plant is rifted by the thunderbolt, cling round it with its caressing tendrils, and bind up its shattered boughs so is it beautifully ordered by Providence, that WOMAN, who is the mere dependant and ornament of man in his happier hours, should be his stay and solace when smitten by sudden calamity; winding herself into the rugged recesses of his nature, tenderly supporting the drooping head, and binding up the broken heart.