48 Remarks on the Crude Sodas of Commerce. 



manufacturer should be able to form a correct judgment in 

 this respect. For this however, our dealers and manufac- 

 turers have a very inadequate standard — they depend almost 

 exclusively on the senses, and the history of the article. The 

 appearance, taste, and weight are their chief guides ; after 

 a long experience, and having paid dearly for that experi- 

 ence, no doubt they can form some general idea of the val- 

 ue of the article, but after all, their judgment, thus formed, 

 must be loose. They generally break a piece of the barilla, 

 and apply the tongue to the fracture ; if the soda be in a 

 caustic state, even though in small quantity, it will excite a 

 much stronger sensation of taste, than when it exists in lar- 

 ger quantity, in the form of a carbonate. Nor is the history 

 of the article more to be relied on, as there are several dif- 

 ferent qualities brought from the same market. Indeed I 

 have known some instances in which the most experienced 

 soap manufacturers, and even large manufacturing chemists, 

 have been most egregiously deceived, by judging of the ar- 

 ticle in this loose way. I lately assayed a sample of artifi- 

 cial barilla, that was sold at eighty dollars per ton, the price 

 of the best in which there was scarcely an appreciable quan- 

 tity of soda, while a sample of Alicant barilla, yielded fifty 

 eight per cent, of pure soda. 



There are a great number of methods, recommended for 

 assaying the crude sodas. An exact assay is undoubtedly, a 

 very nice and even difficult operation, but with a little atten- 

 tion, any manufacturer may make a sufficient approxima- 

 tion for all practical purposes. I have tried several, but 

 would recommend the following as the best ; it is with some 

 modification, the one recommended by Mr. Parkes. 



Take a quantity of diluted sulphuric acid, say six parts of 

 water to one of the sulphuric acid of the shops ; this will be 

 of a convenient strength, and will be found about the specific 

 gravity of 1.100. Select a phial that pours and drops well ; 

 it should have a glass stopper with a score running length- 

 wise along it, and that fits accurately, so that we may be able 

 exactly to fill the phial. With good scales, using a counter- 

 poise for the phial, we should carefully ascertain the precise 

 number of grains of the diluted acid that the bottie will con- 

 tain. Lastly, we must ascertain with nicety the number of 

 grains of the diluted acid that is required to saturate one 

 hundred grains of pure soda. Having made these prepara- 

 tions, we may at any time, in the course of a few hours, de- 



