CHEMISTRY. 



[lNor.i:v\!0 ANALYSIS. 



p. 384. 



T.-t. 

 Soluble salu ... Hydro-sulphorleaddj 



and hydro. >ulphatc V Yellow sulphide. 



of ammonia j 



Potass, &e White oxide. 



Carbonate* of alkalies White carbonate. 



ing potassium and sodium, and tin-ire p..mnk 



:ford insoluble precipitates or other effects 

 similar to those we have described in connection with the 

 metals in the previous list, we pass on to consider tho 

 tests fur the terrigenoous earths and their oxides. 

 Aluminum. See p. 388 



fetation Twtrd. Ttat. BesulU. 



Alumina in sola-) 



lion, as slum, I Potau ^ 1'ite hydrate. 



&c. } 



Ammonia. Do. 



With proto-nitrate of cobalt it produces a sky-blue 

 mass under the blow-pipe, if heated to redness on 

 charcoal. 



Silieon. See p. 389. 



Silica. Its insolubility and general characteristics dis- 

 tinguish silica from every other substance. 



Calcium. See p. 389. 



Solution Tested. Test. Remits. 



^^H 

 Lime, solution 

 of, in water 





Lime salt* 



{The carhonate, or 

 chalk. This preci- 

 pitate is soluble in 

 excess of the acid. 



Sulphuric acid and J The sulphate as a 

 ulphates ........... J white powder. 



Oxalic aciil ............ White oxalate. 



Oxalate of ammonia Do. 



Phosphoric acid 



Do. 



Magnerium. See p. 390. 



Solution TMttd. Teat. BttulU. 



Magnesia ......... Ammonia ............ White hydrate. 



_ :, .................. Do. do. 



Phosphate of soda ... Do. phosphate. 



Oxalate of ammonia Do. oxalate. 



Barium. See p. 31)1. 



Baryta, >alu of Alkaline carbonate... The white carbonate. 

 Sulphuric acid and ) ^ whiu . fu) ^ 

 sulphates ............ J 



Phosphate of soda ... White phosphate. 



'ta of Baryta. Tinged flame of a rich green colour. 



.1. ^See p. 391. 



Mri'iitiii. The tests for baryta exhibit a similar re- 



action with salts of strontia. The sulphate, however, is 



partially soluble in water. The chloride and nitrate 



give a rich red colour to flame, which is highly charac- 



;c of their presence. 



The foregoing tables of tests for metals and their com- 

 pounds, will afford the student an opportunity of making 

 himself acquainted with their leading properties and 

 characteristics ; and will also bo a valuable introduction 

 to the principles on wliich chemical analysis of inorganic 

 bodies is carried on. We should advise that he first 

 prepare the salts of the chief metals, and retain the pro- 

 ducts in both a crystalline and dissolved state. He may 

 afterwards apply the tests we have named to the solu- 

 tions, and note the resulting products. The more ex- 

 tended the course of experiments wliich he may insti- 

 tute of this kind, the more perfect will be his acquaint- 

 ance with the nature of substances he may afterwards 

 meet with, or which are produced in analytical investi- 

 gations. In fact, without such a preliminary study, his 

 attempts at analysis will prove but guess-work, resulting 

 in disappointment and loss of time. 



CHAPTER V. 

 INORGANIC ANALYSIS. 



HATINO described the chief properties of all the elemen- 

 tary bodies wliich the student is likely to meet with ; 

 and having also mentioned the different testa which may 

 be employed to detect their presence, and that of their 

 compounds, we shall proceed to describe the methods 

 adopted by chemists in discovering the composition of 

 bodies which may be casually presented for examination, 

 ed scarcely say that the object of an analysis is 

 to find out either the proximate or ultimate elements of 

 which a substance is compounded. In most cases we are 

 content to find the proximate substance, rather than to 

 separate the elementary bodies entirely from each other. 

 Thus, for instance, in analysing a piece of limestone, 

 we are content to find how much lime, magnesia, itc. , 

 it may contain ; and ilo not trouble ourselves about the 

 metals of which those earths are the oxides. I 



however, we must ascertain the quantity of the 



V4SMWD, itwn v vs . n v 111 tmi> om\>^i Mtiu viiv t^uitii 1,1 \, j \ii vuu 



elementary body present. Thus, in examining the ores 

 of gold and silver, we always desire to ascertain how 

 > of the pure metal is present. But chemical analysis 

 may be divided into two parts ; that is, qualitative and 

 quantitative analysis. Ky tho former, we merely ascer- 

 tain tin- fact that a body is present ; but by the latter, 

 we arrive at a knowledge of its quantity in any substance 

 which may be analysed. 



(Qualitative analysis always precedes that of quanti- 

 tative ; because, of course, we must first detect the 

 presence of a body before we can ascertain in what pro- 

 ]K>rtifin it exists. Wo shall, therefore, first draw the 

 attention of our readers to that branch of the science, and 

 point out tho" various methods wliich may be adopted. 



rally speaking, substances presented for analysis 



tain several com pounds ; nnd it reunites considerable 



skill to apply tho projicr test, so that only one compound 



at a tituu shall be removed or detected. Fur instance, 



supposing a solution contained both sulphuric and hydro- 

 chloric acids. If one of nitrate of silver were add. 

 it, then both acids would be precipitated together as 

 the sulphate and chloride of silver ; and they would 

 either have to be separated by troublesome processes, or 

 be left as an un resolvable mass. But if we first preci- 

 pitate the sulphuric acid, by means of nitrate of baryta, 

 in the form of the sulphate of that earth, we shall only 

 leave nitric and hydrochloric acid and their compounds 

 in solution. We filter off the insoluble sulphate of 

 baryta ; and pouring the clear liquid into another %< 

 we may then add nitrate of silver, when all tho chlorine 

 will combine with the metal as the chloride, which will 

 then bo precipitated. 



But even in this simple process another precaution 

 must be attended to; for if, in the last case, we added 

 chloriilc of barium to tho solution, for the purpose of 

 precipitating the sulphuric acid, then we should intro- 

 duce nioro chlorine, into the liquid, wliich would be 

 thrown down on the addition of tho nitrate of silver: 

 hence, such a careless analysis would afford far more 

 chlorine than should really h;n<- been present. This 

 instance will suliico to show that wo must not try tests 

 at random, but in an orderly and consecutive manner; 

 which is a point of grmit importance to the young student; 

 formany nture, and so only su. 



in confusing themselves becoming frequently dis- 

 gusted at their want of success. We ha\e MH such 

 take the first out of a row of test-bottles, and trying one 

 tiling after another, in the vain hope of discovering tho 

 substances contained in a solution ; and after expending 

 considerable time in a chemical have 



i with the . ihal they could not undertake 



is ; in which opinion their tutors have often most 

 rationally acquiesced. 



