210 



ANALYSIS. 



productions warranted her to conceive she \\:i~ a 

 prophetess. As her prophecies in the troubled 

 times of Charles I. were usually against the govern- 

 ment, she was at length brought by them into the 

 court of high coinmiion. The prophetess was 

 not a Hull- mad, ami fancied the spirit of Daniel 

 was in her, (mm an anagram she had formed of her 

 name, Eleanor Davies to Reveal O Daniel. The 

 anagram hud too much by an /, and too little by an 

 s ; yet Daniel, and Reveal were in it, and that was 

 sufficient to satisfy her inspirations. The court 

 attempted to dispossess the spirit from the lady, 

 while the bishops were in vuin reasoning the point 

 with her out of the scriptures, to no purpose, she 

 poising text against text. One of the deans of the 

 Arches, says Heylin, took up a pen, and at last hit 

 upon this excellent anagram: Dame Eleanor Dames 

 Never so mad a ladie I The happy fancy put the 

 solemn court into laughter, and Cassandra into the 

 utmost dejection of spirit. Foiled by her own 

 weapons, her spirit suddenly forsook her; and either 

 she never afterwards ventured on prophesying, or 

 the anagram perpetually reminded her hearers of 

 her state. No more was heard of the prophetess." 



ANALYSIS, CHEMICAL, OF INORGANIC 

 BODIES. The aim of an inorganic analysis is to 

 determine the constituents of an inorganic substance, 

 and their proportions by weight. This department 

 of chemistry has made great and rapid progress 

 within the last few years, and analysis has now be- 

 come an art within the compass of fixed rules. In- 

 organic analysis is of two kinds qualitative and 

 quantitative ; the former should always precede the 

 latter. Attention must first be given to the physical 

 properties of the substance ; it may be volatile, or 

 combustible, capable of being sublimed, or it may 

 be decomposed by heat. In order to separate the 

 constituents of a body, it must in general be dis- 

 solved. For this purpose, pulverisation must fre- 

 quently be first had recourse to; the effect of water 

 is tried, and then of the mineral acids, if it prove in- 

 soluble or only partially soluble in water. The ab- 

 sence or presence of a particular body in this solution 

 is found by the bringing small portions of it in con- 

 tact with known compounds called reagents. From 

 the appearances that present themselves, the opera- 

 tor is enabled to determine whether this or that 

 substance be present in the substance tested. A 

 practical acquaintance with the use of reagents, is 

 absolutely necessary for the performance of every 

 analysis. The changes produced by reagents are 

 frequently escape of a gas, a precipitate, change of 

 colour, &c. The more usual reagents are sulphur- 

 etted hydrogen, potash, ammonia, sulphuric and 

 muriatic acids, ferro-prussiate of potash, &c. Many 

 cases present themselves, particularly of siliceous 

 minerals, which do not dissolve in the mineral 

 acids, and which, to be analysed, must be brought 

 into solution, by being previously fused with car- 

 bonate of potash; the constituents of the mineral 

 are now found soluble in muriatic acid, with the 

 exception of the silica, which remains in the form 

 of a jelly. The reagents are applied to the solu- 

 tion, separated from the silica, in the same way as 

 to solutions of substances in muriatic acid, which 

 have not been previously fused with potash. 



Having determined what are the ingredients of a 

 substance, the next step is to determine the rela- 

 tive proportions of each. This is done by obtain- 

 ing each of the substances, separated into com- 

 pounds of known composition ; not, or but seldom, 

 by obtaining the substances themselves pure and 



uncombined with any other. Thus it is more 

 usual to dett-rmim' the proportion of sulphur in a 

 compound, by converting it first into sulphuric acid, 

 und then into sulphate of barytes, than by obtaining 

 the sulphur in the simple form. The composition 

 of sulphate of barytes is well known, the pur cent- 

 age of sulphur it contains has been rigidly ascer- 

 tained, and it is therefore now become a mere 

 matter of convenience to extract the sulphur in the 

 simple form, or to obtain it in a known compound. 

 In the same way the ores of iron are analysed, by 

 obtaining the peroxide of iron they contain, and 

 from thence calculating the amount of iron, and so 

 on, of hundreds of minerals and other substances. 

 As according to the theory of definite proportions 

 (see Atomic Theory'), every chemical compound 

 contains always the same proportions of its in- 

 gredients, it is frequently sufficient to ascertain, 

 by experiment, the amount of one of the ingre- 

 dients of a substance, to be enabled to calculate 

 precisely the amount of another ingredient. Thus, 

 one way of analysing limestone is to measure or 

 weigh the carbonic acid it contains, and thence to 

 calculate the amount of lime in the mineral. When 

 a substance contains many ingredients, its analysis 

 is often troublesome in the extreme, and demands 

 for its execution a stock of untiring perseverance, 

 and the greatest accuracy. The reagents in such 

 cases must be applied in a certain order; thus, to 

 choose a very simple instance, the mineral garnet 

 contains silica, alumina, lime, and oxide of iron. The 

 mineral must be dissolved in muriatic acid, eva- 

 porated to dryness, and the silica thrown on a fil- 

 ter ; the solution contains lime, alumina, and oxide 

 of iron ; to this solution caustic ammonia is added, 

 which throws down the two last, but retains tjhe 

 first in solution; the precipitate is collected on a 

 filter, and the lime which comes through is preci- 

 pitated by oxalate of ammonia ; the resulting oxa- 

 late of lime being dried and calcined, gives carbo- 

 nate of lime, a compound of lime of well known 

 composition. To return to the alumina and oxide 

 of iron which we left precipitated on the filter, 

 these must be ledissolved in muriatic acid, and re- 

 precipitated, and boiled with caustic potash. The 

 alumina dissolves entirely, and leaves the oxide of 

 iron pure. 



The analysis of mineral waters is a very impor- 

 tant branch of inorganic analysis. The substances 

 dissolved in water may be ga=es or solids. Many 

 springs contain large quantities of carbonic acid dis- 

 solved in water; its amount is known by bringing 

 a known bulk of it in contact with an ammoniacal 

 solution of chloride of calcium; the carbonate of 

 lime which precipitates, being collected and weighed 

 affords a correct indication of the quantity of car- 

 bonic acid contained in the water. The solid con- 

 tents of a water are ascertained by evaporating to 

 dryness a known quantity of water ; and testing 

 the salts obtained like any other inorganic com- 

 pound. The presence of iron is best ascertained 

 by immersing in the water a bit of gall-nut ; if this, 

 after the lapse of half an hour or so, strike an inky 

 colour, the water contains iron. Common salt is 

 tested by the amount of precipitate afforded by ni- 

 trate of silver. 



ANALYSIS, CHEMICAL, OF ORGANIC 

 BODIES. Organic bodies generally contain only- 

 three or four constituents; these are carbon, oxygen, 

 bydrogert and nitrogen. Nitrogen is contained in a 

 comparatively small number of vegetaole substances, 

 but is most usually, though by no means always, to be 



