213 



ALIZARIC ACID. 



ALKALIMETRY. 



214 



The aliquot parts omitted contain fractions of farthings, and are 



This table shows all the aliquot parts of a pound down to one half- 

 penny : for example, we see ;2j, signifying twopence-halfpenny, opposite 

 to ttcdfth under eighth, which shows us that 2J is the twelfth part of 

 the eighth part of a pound. If, therefore, we wished to find how much 

 3715 yards cost at 2J</. a yard, instead of multiplying by 2}, and 

 dividing by 12 and 20,"we should divide by 8 and 12, as follows : 

 8 ) 3715 



12 ) 464 7 6 

 38 13 lli 



[PRACTICE.] 



ALIZARIC ACID. [MADDER.] 

 ALIZARIN ACID. [MADDER.] 



ALKALIES. Although the tenn alkali (compounded of the Arabic 

 prefix al, and kali the name of plant-ashes, from which potash is 

 obtained) >vas formerly rather loosely applied to a variety of basic 

 substances, yet its use is now generally restricted to three metallic 

 oxides, namely, potash (KO), soda (NaO), and lithia (LiO), which from 

 their non-volatility at a red heat are termed the f.red alkalies, and to 

 ammonia, a compound of nitrogen, hydrogen, and oxygen (NH 4 0), 

 whii-li on account of its volatility, even at ordinary temperatures, is 

 sometimes called the ro/alile alkali. 



The chemical properties of the alkalies are the following : their 

 aqueous solutions turn vegetable blues green, and vegetable yellows 

 reddish-brown ; hence infusion of red cabbage and infusion of turmeric, 

 or papers stained with them, are used as tests of the presence of an 

 alkali. The alkalies restore the colour of vegetable blues as of litmus, 

 for instance which have been reddened by acids, and, on the other 

 hand, the acids restore vegetable colours which have been altered by 

 the alkalies. These properties are also common to lime, baryta, and 

 strontia. 



The alkalies have great affinity for, and readily combine with, acids, 

 forming *alt, and the power of both in altering vegetable colours, is 

 then destroyed. The alkalies are separated at the negative pole of the 

 voltaic decomposition cell. 



Potash and soda destroy the skin when applied to it nrconcentrated 

 solution. These alkalies, together with lithia, are inodorous, but 

 possess a peculiar acrid taste. Ammonia has a similar taste, and 

 possesses a very pungent odour, like hartshorn, or smelling tails. All 

 the alkalies are very soluble in water. For their preparation, special 

 properties, and uses, see POTASH, SODA, LITBIA, and AMMONIA. 



ALKALIES, Mediml Prnpertie of. It is impossible to exclude 

 magnesia and lime from consideration when treating of alkalies, 

 but the remarks which follow are chiefly intended to apply to soda, 

 potassa, and ammonia. The two former are 1 termed fixed, the latter 

 volatile : soda is likewise termed the mineral or fossil alkali ; while 

 potassa is termed the vegetable alkali, or sometimes merely kali. The 

 Baits formed with alkalies are apt to effloresce, and resolve the crystals 

 into the state of powder, or to absorb water from the air, and deliquesce 

 or become liquid. 



Alkalies in a pure state are extremely caustic, destroying the tissues 

 with which they come hi contact, and forming an eschar which is deep 

 if the alkali be confined, extensive and superficial if allowed to spread 

 Thin seems to depend on then- strong affinity for water : hence they 

 act as violent corrosive poisons, and are never used in a pure state 

 save in surgery to open abscesses or to form caustic issues. Dilutee 

 with oils they constitute rubefacients, particularly ammonia. Their 

 causticity is also greatly lessened by combination with carbonic acid 

 and is more subdued by an excess of the acid ; hence bi-carbonates are 

 less caustic than sesqui-carbonates, and these last than carbonates 

 Carbonate of ammonia will altogether disappear if not kept in a wel 

 topped bottle ; this tendency is one source of its utility when used as 

 smelling salts. 



When suitably diluted with water or by combination with carbon; 

 acid, so as to be safely applied to the tongue, alkalies have a taste 

 peculiar, and to most persons unpleasant, which is designated olfrn/!af 

 for want of anything similar to which to liken it. Ammonia and it* 



carbonates are likewise pungent. They exercise an immediate influence 

 on the fluids of the mouth and alimentary canal, as far as they pass 

 mchanged. They neutralise all acids they meet with in their course, 

 nd render the mucus, and perhaps some other secretions, thinner and 

 more watery. That they are readily absorbed into the circulating 

 mass, on which they have a marked influence, is certain ; but they are 

 or the most part speedily eliminated, the kidneys appearing to be the 

 hannels by which they are thrown out of the system. Many alkaline 

 Compounds, as well as the uncombined but diluted alkalies, increase 

 he secretion of urine, and change its nature, if long persevered in, 

 iltering it from an acid to an alkaline state. This is particularly the 

 case when the compound is one of carbonic acid, or of a vegetable acid 

 with the base, all of which are decomposed in transilu, as first remarked 

 by Sir Gilbert Blane, and produce on the urine, and the system gene- 

 rally, ultimately the same effects as the pure alkalies. The alkalies 

 >ossess a power of rendering albumen soluble : unboiled white of egg is 

 in albuminate of soda. The albumen of the blood is rendered more fluid 

 >y alkalies ; hence in excess they impair the plastic power of that fluid. 



These facts seem all that are requisite to form a correct estimate of 

 ,heir therapeutic powers and employment. Their caustic and rube- 

 acient properties fit them for external use. Their internal employment 

 s regulated by a variety of indications, but it is chiefly as antacids, or 

 f> counteract acidity in the stomach and prima I'ice, and as diuretics, 

 and to dissolve calculi in the kidneys or bladder, and as refrigerant or 

 cooling medicines in inflammatory diseases, that they are used. Many 

 persons, soon after food has been taken into the stomach, are distressed 

 ith heartburn and other signs of indigestion, and either have the 

 urinary secretion in an unhealthy state, or, if they be of a gouty dis- 

 >osition, have frequent attacks of gout. Such persons feel relief by 

 aking some alkaline medicine after meals, or have recourse to them 

 jecause others use them. When uric or lithic acid exists in the urine, 

 such means may be proper ; but this point should be ascertained before 

 laving recourse to measures which, when not appropriate, are far from 

 jeing harmless. Some acid, either hydrochloric or acetic, is essential 

 ;o sound digestion : to neutralise these is to retard and disturb that 

 process. Other acids, especially lactic, in bilious persons and those 

 irho use sugar or saccharine fruits in excess, occur, and require to be 

 obviated ; but the proper time for taking, as well as the proper quantity 

 to be taken, requires much judgment. Assuming that some alkali is 

 proper, Sir B. Brodie thinks from three to four hours after each of the 

 principal meals, especially dinner, the most suitable time. (' Lectures 

 on the Urinary Organs,' 3rd ed. p. 203 ; and ' Medical Gazette,' vol. 

 xxiii. p. 151.) Dr. Prout makes a similar remark with respect to alka- 

 line mineral waters. A variety of circumstances regulate the alkali to 

 be selected. From their greater causticity, the pure alkalies can rarely 

 be persevered in sufficiently long, even when token in such bland 

 vehicles as veal-broth. The alkaline carbonates are better borne, and 

 bi-carbonate of potass more easily than carbonate of soda. Their 

 unpleasant taste constitutes an objection with many : this is in some 

 degree obviated by giving them in the condensed form recently devised 

 by Mr. Brockedon, or in an effervescing state with an excess of alkali, 

 as recommended by Sir Gilbert Blane. If taken unnecessarily or per- 

 severed in too long, much evil is done : not only is an alkaline state of 

 urine induced, with a deposition of the phosphates, as indicated by a 

 white sabulous sediment, or an iridescent pellicle on the surface of the 

 urine, but much general debility is caused. " Other ill consequences 

 follow the too liberal use of alkalies : they alter the quality of the 

 blood. After some time the patient is liable to petechiffi ; he perspires 

 too easily, becomes low-spirited, and less capable than when in health 

 of physical exertion." (Brodie, I. c. p. 202.) As effervescing or saline 

 draughts, made with a vegetable acid -and some alkaline carbonate, are 

 much used at the beginning of inflammatory diseases for their reducing 

 and refrigerant effects, the same caution is requisite lest they be pushed 

 too far. Tlu's is also needful in the case of soda-water (when it really 

 contains soda, and not merely carbonic acid, as is frequently the-case), 

 citrated alkali, imperial, and other drinks much used in warm weather. 

 Scrofulous persons can least of all bear up against the abuse of these, 

 yet for such are they unfortunately most employed. Weak vegetable 

 acids will be found more beneficial. 



ALKALIMETRY, a term applied to certain ready methods of esti- 

 mating the commercial value of the alkalies, more especially of potash 

 and soda, and of certain of their salts which possess an alkaline reaction. 

 The most simple method of performing this operation consists in ascer- 

 taining the amount of a dilute acid of known strength required 

 exactly to neutralise 100 grains of the sample of alkali. The alkalies 

 and alkaline salts generally tested in this way are potash, soda, and their 

 carbonates. For most of the purposes to which these materials are 

 applied in the arts, then- value depends upon the quantity of the 

 alkali which they contain, either in a caustic state or in the condition 

 of carbonate ; other alkaline salts or compounds that may be present 

 being useless, if not deleterious. As soda is much more largely used 

 in the arts than potash, the standard acid, or test add, as it is termed, 

 is often made with reference to this alkali, and is graduated to such a 

 strength that 1000 grain measures of it exactly neutralise 100 grains 

 of anhydrous caustic soda (NaO) ; but the following method of pre- 

 paring the test-acid, recommended by Faraday, is the most con- 

 venient and generally applicable, both to potash, soda, and their 

 carbonates. The test-acid employed is measured from an instrument 



