78 PRACTICAL AGRICULTURAL CHEMISTRY [262 



i Round brown stoneware trough, 12 inches across, 

 5 inches deep. 



1 Metal deflagrating-spoon. 



2 Two-necked Woulffe's bottles, 8 oz. capacity. 



1 Tubulated retort, 6 oz. capacity. 



2 Thistle funnels, 8 inches long. 



4 Pieces of black indiarubber tubing, ^ inch in internal 

 diameter, 1^ inch long. 

 Wooden spills. 

 Wax tapers. 

 1 Pair of scissors. 

 1 Brass wire sieve, 20 meshes to the inch. 



List of Apparatus for General Use in Analysis 



262: The following apparatus should be kept in the 

 laboratory for the general use of students. One set will 

 suffice for about twelve students. 



1 Spirit-lamp, 4 oz. capacity, with earthenware wick- 

 holder and ground glass cap. 



If gas is not available a set of these lamps will be required in place 

 of Bunsen burners (260). 



4 Berlin porcelain crucibles, 1 \ inch across, with covers. 



1 Iron mortar, 8 inches across, with pestle. 



1 Fletcher's foot-bellows and blowpipe- table covered 

 with sheet zinc or lead. 



1 Fletcher's blowpipe with central blast and 2 taps. 



1 Indigo prism, stoppered, nearly filled with solution of 

 indigo in strong sulphuric acid. The indigo solution is 

 made by mixing commercial sulphindigotic acid with ten 

 times its measure of strong sulphuric acid, leaving to settle 

 for several days and decanting into the prism. 



N.B. — Cobalt-blue glass may be substituted for the 

 above. 



1 Agate mortar, 3 inches across, and pestle. 



1 Copper water-bath, with several openings (fig. 11). 

 When in use it should be two-thirds filled with water, and 



