Prof. Fiichs 07i the Examination of Malt Liquors, 219 



lution is weighed, and the loss of weight is the carbonic acid, which 

 suppose to be 1^ grain, which is about the quantity contained in 

 good beer. 



The contents of the glass vessel are poured into the '* Hallymeter," 

 taking care that no portion of the undissolved salt is left behind ; the 

 undissolved salt must be brought into the smallest possible space by 

 being shaken down until it will not sink any lower in the tube, which 

 will require 15 minutes. By referring to the graduated scale on the 

 tube, it will show how much salt remains undissolved ; this quantity, 

 deducted from the quantity first taken, will give the quantity dis- 

 solved. Thus 330 grains of salt added to 1000 grains of beer, gave, 

 by trial, 17*3 grains of salt undissolved; therefore 17*3 from 330 

 give 312*7 grains dissolved, which is equal to 868'61 grains of water, 

 (36 grains of salt being dissolved by 100 of water) ; this 868*61 

 grains, deducted from the 1000 grains of beer under examination, 

 leaves 131*39 grains as the whole of the ingredients contained in the 

 beer. 



Second process {for ascertaining the weight of the extract only). — 

 Another portion of 1000 grains of beer is taken and evaporated 

 down to one half, by which means all the spirit of wine is driven 

 off; it is cooled and weighed, and treated with a proportionate quan- 

 tity of salt as before. In ordinary cases it is advisable to add 180 

 grains of salt to the evaporated solution ; thus, if to the 500 grains 

 180 grains of salt have been added, and there remain 21*3 grains 

 of salt undissolved, then 158*7 grains have been dissolved, which is 

 equal to 440*83 grains of water; this, deducted from 500 grains, 

 gives 59' 17 for the extract ; now add to the extract 1*5 for carbonic 

 acid (as by first process), and deduct this amount 60*67 from the 

 quantity found by the first process, 131*39; there remains 70*72 

 grains for the spirit of wine. 



The 1000 grains of beer therefore consist of 

 868*61 water, 

 70*72 spirit of wine, 

 59*17 carbonic acid, 

 1*50 extract. 

 1000* 

 As it is necessary that the common salt should be chemically 

 pure, Mr. Fiichs has given the following process for obtaining it from 

 ordinary salt. 



Purification of Common Salt. 

 The salt is dissolved in lime-water, or if it contains much mag- 

 nesia, in very weak cream of lime. To the clear solution muriate of 

 barytes is added as long as any precipitate falls ; it is then filtered, 

 and carbonate of ammonia, with a little caustic ammonia, is added, 

 by which the lime and excess of barytes are precipitated. After stand- 

 ing 24 hours, it is tested by oxalate of ammonia ; and if no cloud- 

 iness ensues after two hours, it is free from lime. The clear solu- 

 tion is then evaporated, and the residue submitted to a low red heat ; 

 a saturated solution, exposed to a temperature of about 50° Fahren- 

 heit, [query 30°,] deposits crystals of pure salt. 



