FORMATION OF INDIGO-BLUE. 215 



in ether. When heated in a tube it was completely volatilised 

 without melting, forming a sublimate on the colder parts of 

 the tube in the form of a light mass like cotton. It was easily 

 soluble even in the cold in sulphuric, muriatic and nitric acids. 

 The solution in nitric acid gave off no nitrous fumes on being 

 boiled and left on evaporation a colourless syrup, which on 

 standing was changed into a crystalline mass. The solution in 

 muriatic acid left on evaporation a crystalline residue. It 

 was easily soluble in caustic soda, and the solution evolved no 

 ammonia on being boiled, but when the dry substance was 

 heated with soda-lime it gave off a strong smell of ammonia 

 accompanied by a peculiar penetrating odour. The watery 

 solution was neutral to test paper and had no perceptible 

 taste. When mixed with freshly precipitated oxide of copper 

 and boiled, the watery solution became sky-blue ; the filtered 

 liquid gave no precipitate with caustic soda, and on being 

 evaporated left a residue consisting of bright blue crystals. 

 The watery solution gave no precipitate with nitrate of silver, 

 but on the addition of a little ammonia there was deposited 

 almost immediately a quantity of small crystalline scales, 

 which blackened slightly on exposure to the light, and were 

 not easily soluble in an excess of ammonia. The watery 

 solution gave no precipitate with acetate of lead, and even on 

 adding ammonia there was only a slight precipitate, but on 

 allowing the ammoniacal liquid to stand for some hours there 

 was formed a crystalline mass of a pearly lustre consisting 

 of needles arranged in star-shaped masses. 



The analysis of the substance gave the following results: 



0.3430 grm. dried at 100°C. and burnt with chromate of 

 lead gave 0.6820 grm. carbonic acid and 0.3125 water. 



0.2550 grm. gave 0.4125 grin, chloride of platinum and 

 ammonium. 



The composition in 100 parts agrees tolerably well with 

 required by the formula of leucine C 12 H| S N0 4 , as will 



