§ 89. cour.SE OF qualitative analysis. 129 



scribed tbere, nor such ns in ; therefore, carbonic acid 

 and sulphur are absent ; we do get, however, the fine 

 white ^precipitate as described in 9, and note sulphuric 

 acid as present ; we also get a yellow j)recipitate in 10, 

 and make a note of phosphoric acid as present ; we do 

 not get the reaction in 11, but get a white precipitate in 

 12, the formation of which, under the circumstances, indi- 

 cates that cyanogen, iodine, ferrocyanogen, or chlorine, 

 may be present ; a precipitate would be given also by 

 sulphur, if that were present, but the test for this element 

 has already been made ; we do not find the first three 

 substances named above, and learn in 16 that, consequent- 

 ly, chlorine is present ; we find no nitric acid in 17, and, 

 as the substance is not blackened when heated as directed 

 in 18^ no organic acids are present, and we have finished 

 the examination for tlie acids. 



Passing to the detection of the bases, we have the 

 question in 1 already answered for us, with this small 

 difference, that, in the examination for the bases, a hydro- 

 chloric-acid solution is preferable to a nitric-acid solution ; 

 going on to 3, we add sulphuric acid, and get no reaction, 

 even after the mixture of substance and reagent has stood 

 some time ; no lead or barium, and, at the most, only 

 traces of calcium, can be present ; passing on to 7 we find 

 no ammonium; we get the violet color, indicating potas- 

 sium, in 9, after having properly prepared the solution as 

 directed in 8 ; and so working on, we find no copper in 

 10, but do get iron in 11, and manganese in 15, and after 

 that, nothing more before reaching tbe end of the course. 



It will be noticed that sulphuretted hydrogen and am- 

 monic sulphide, and also the blowpipe, are used but little 

 or not at all in this course of analysis ; there are suffi- 

 ciently good reasons why their use should be dispensed 

 with, if it can be done without impairing the reliability 

 of the work. 



The plan of the course for the bases coiTcsponds in the 

 6* 



