PROCEEDINGS OF SECTION B. 333 



2.— THE TECHXICAL EXAMINATION OF BOILER 

 WATERS. 



By W. A. HARGREAVE8, M.A., FJ.O., and W. T. EOJFE. 



The quantity of literature upon this subject is so gi'eat that some 

 apology would seem necessary for further increasing it, but it is chiefly 

 on account of this very abundance that it is advisable now and again to 

 attempt to compile bi-ief methods embodying the results of the researches 

 of others. No originality is therefore claimed for any of the details 

 about to be set out. nor even for the general principles contained in the 

 method. All that we state is that a working scheme has been evolved 

 based on the suggestions of others too numerous to individually acknow- 

 ledge, which appears, so far as our experience goes, to be an improve- 

 ment on any methods that we have seen published. 



In this country, where so many raw waters previously untested or 

 analysed have to be taken into use. much of the work of the analyst is 

 of a pioneering nature, and it is necessary that he should make a large 

 number of rapid examinations rather than detailed analyses of a few 

 samples made with the greatest accuracy possible. 



The following scheme will be found to permit of these fairly rapid 

 examinations being made with an accuracj^ very closely approximating to 

 that given by a detailed analysis by ordinary methods. 



SCHEME FOR ANALYSIS OF SALTS IX BOILER WATERS. 



Determine the following : — 



1 . Alkalrnity [■=. A), by titrating 70c. c. of the sample with N/i o HCl. 

 and methyl orange. — Let a c.c. be required. 



Then A (^i.e. alkalinity) = oa 



= Ht. -f NaoCO:, (in terras of CaCOs) 

 = total CO 3 (in terras of CaCOg) 



Permanent Hardness (= Hp). — Boil 70c. c. of the water with con- 

 siderable excess {i.e., at least 30c. o. in one and 40c. c. in the duplicate) 

 of N/io Na^CO:, for half an hour (or until reduced to small bulk), 

 filter while hot, wash three times (not more) with boiled hot distilled 

 ■water, titrate filtrate with N/io HCl. and methyl orange. 



Let N be the quantity of N/i o NaaCO., taken, and n c.c. N/^^ HCl 

 be used in the titration. Then Hp = 5 (N — n), and I'otal Hardness 

 = H ^ Hp -f- A {i.e. the algebraical sum) and Temporary Hardness = 

 Ht = H — Hp. 



If the water contains NaoCOa, the Hp. will be a minus quantity, 

 and its amount represents the NaoCO 3 in terms of Ca.COg. If the 

 Hp is zero or a positive quantity, there is no Nag CO 3 in the water, and 

 then A = Ht. 



Hardness due to Calcium (= Ilea). — Boil 350c. c. of sample with few 

 drops HNO;, ; then add about 0-5 gramme of AmCl, make alkaline with 



