1870.] Chemistry. 531 



pulverized and next completely incinerated; the ash is triturated 

 in an agate mortar and lixiviated with water ; the residue is treated 

 with very pure nitric acid, and the solution thus obtained is 

 evaporated to dryness and calcined in a test-tube ; after cooling, a 

 few drops of nitric acid are added, and the contents of the tube again 

 boiled ; next a few grains of puce-coloured oxide of lead are added 

 and the liquid again boiled ; a more or less deeply purplish-coloured 

 liquid appears on leaving the tube at rest for a short time, which 

 is due to the formation of permanganic acid. No quantitative re- 

 searches have as yet been made by the author. 



All chemists must have suffered inconvenience by finding that 

 their test-solution of tartaric acid had become mouldy. Many re- 

 medies for this decomposition have been suggested, but none appear 

 so simple as the one proposed by William H. Wood, of Middles- 

 bro'-on-Tees. This chemist has made known that if a solution of 

 tartaric acid in water, whether mouldy or not, be filtered and then 

 boiled for a short time (say ten minutes), it will not afterwards be- 

 come mouldy, whether corked or stoppered up in a bottle, or left 

 exposed to the ah*. This statement will, if confirmed, be important 

 as bearing on the so-called " spontaneous generation " controversy, 

 and may throw some light on it. 



The production of a crystalline alloy of zinc and calcium has 

 been observed in the preparation of calcium by the process of 

 M. Caron, in which an excess of zinc was employed. It contains 

 about 95 per cent, of zinc and 5 per cent, calcium, corresponding 

 to the formula Zn 12 Ca. These crystals are small octahedrons with 

 square bases. They are acted upon by water with the liberation 

 of hydrogen. 



Dr. W. Stein has devised an easily-executed process for the 

 detection of madder colours upon cloth or by themselves. He 

 boils the cloth with a concentrated solution of sulphate of alu- 

 mina, whereby a liquid is obtained of reddish colour, exhibiting 

 a golden-greenish fluorescence, due to the presence of purpurine; 

 the behaviour of the colouring matters of madder towards sulphate 

 of alumina is so characteristic that this salt may serve as an effec- 

 tive test for these substances ; the alizarine may be readily rendered 

 soluble by treating the dye material or dyed cloths with alcohol 

 acidified with hydrochloric acid. 



As a result of a lengthy series of experiments, M. E. Baudri- 

 mont concludes that tin-foil, in consequence of its impermeability 

 for water, may serve with great effect to protect various substances 

 from the effects of the atmospheric moisture, as well as act as a 

 protective against the alterations fruit undergoes by evaporation of 

 the fluids therein contained ; tin-foil also protects against the oxi- 

 dizing action of the oxygen of the atmosphere, and may hence serve 



