Apparatus for Analyzing Calcareous Marl, ^c. 301 



the former be used the end of the tube must be partially closed with 

 a perforated cork. The tube C which contains the muriatic acid is 

 furnished with a light piston of cork or cotton, in the center of which 

 is fixed a rod or handle made of a small stiff straw. This instrument 

 when charged with the usual quantity of marl and acid does not 

 weigh more than 120 grains. The whole load of the beam is there- 

 fore about 240 grains, and it is still sensible to y^^ of a grain. 



The mode of proceeding with the analysis is as follows. Five 

 or ten grains of the finely pounded marl or other carbonate are intro- 

 duced into the vessel A, and then two or three drops of water added, 

 to assist the diffusion of the acid. The small end of the tube C, 

 now removed from the cork is dipped into muriatic acid in a 

 wine glass and the piston moved backwards and forwards until the 

 necessary quantity of acid has been drawn in. The tube is then 

 replaced in the cork and in this state the instrument is counterpoised 

 by weights in the opposite scale. The piston being then gradually 

 forced in, the acid is injected drop by drop upon the marl or other 

 carbonate, and the gas escapes by the tube B, depositing the mois- 

 ture m its passage on the muriate of lime or cotton. Allowing the 

 apparatus to rest in a dry place until the gas has entirely escaped, 

 and the decomposition is complete, the equilibrium is restored by 

 placing weights upon the top of the cork, or by removing weights 

 from the scale. In this way the weight of the disengaged gas is ac- 

 curately determined and the proportion of carbonate thence compu- 

 ted. 



The following analysis of a specimen of marl from James city, Va. 

 may serve as a useful illustration of the method, to such of your 

 readers as are interested in the application of calcareous manures. 

 Ten grains of the finely powdered marl were introduced with a little 

 water into the vessel A, the instmment was then charged and equi- 

 poised. The acid being injected, the whole was allowed to rest. — 

 The weight lost was 2.91 grains. Increasing this in the ratio of 100 

 to 44 gives 6.61 grains of carbonate of lime in the ten grains of 

 marls, or almost precisely 6Q per cent. 



The bulb of this apparatus is very readily formed of a common 

 test tube about | of an inch in diameter, the lower end of which 

 admits of being blown out into a thin sphere of the proper size. — 

 The neck is then filed off short and a cork adapted. Any ordinary 

 worker in glass will construct the instrument, and skill in manipulating 

 with it may be soon and easily acquired. 



