672 Chronicles of Science. [ Oct., 
with sulphuric acid and exposed to the vapour of bromine. It then 
instantaneously assumes an intense violet colour, varying in shade 
according to the amount of the substance present, but sufficiently 
distinct with 0°0005 of a gramme. M. Lefort’s investigation was 
confined to the different properties of the various digitalines found in 
commerce ; and we may say in a few words that the differences re- 
marked were so great as to show that digitaline at the best is an 
extremely variable substance, the use of which as a medicine should 
at once be prohibited. 
A lamentable occurrence at Liverpool has been the occasion of 
some experiments on the chemical properties of the Calabar bean by 
Dr. Edwards,* which will be found of great interest to toxicologists. 
While on the subject of the detection of vegetable poisons we 
must mention that Dr. Helwig t has found that by a very carefully 
regulated temperature morphia, brucia, strychnia, veratria, aconitia, 
and atropia may be sublimed, and the microscopic appearance of the 
sublimate become the means of identification. 
Cahours, whose experiments on the respiration of leaves and 
fruits we noticed in our last, has proceeded with an examination of 
the respiration of flowers.t The green parts of plants, it will be 
remembered, under the influence of light assimilate carbon and give 
off oxygen ; the coloured parts, on the contrary, absorb oxygen and 
evolve carbonic acid. 
In analytical chemistry we have but little to report. Professor 
Williamson and Dr. Russell detailed to the Chemical Society a new 
method of gas analysis, no description of which would be intelligible 
unless accompanied by a drawing of the apparatus employed. We 
must therefore refer the reader to the ‘Journal of the Chemical 
Society’ for the description. 
M. Schlosing has quite recently $ published a method of esti- 
mating phosphoric acid in earthy phosphates by reducing the acid in 
‘a current of carbonic oxide, and subsequently passing the volatilized 
phosphorus into a solution of nitrate of silver. The phosphide of 
silver which is formed is then converted into phosphate and weighed. 
This process is not likely to meet with general adoption. The deter- 
mination of phosphoric acid is, however, a very important matter, 
especially to the agricultural chemist, and we therefore call attention 
to a valuable paper on the analysis of mineral phosphates by Mr. 
R. Warrington, jun.,|| which contains a detailed description of the 
best methods hitherto pursued. 
In the technical applications of chemistry one or two important 
discoveries have been made. The first we may notice is that of 
M. Pelouze,{ who has found that the alkaline polysulphides saponify 
fats as easily as caustic alkalies. This discovery may considerably 
* «Chemical News,’ vol. x. p. 108. 
+ ‘Zeitschrift fiir Analytische Chemie,’ H. 1, 1864, ° 
{+ ‘Comptes Rendus,’ June 27, 1864. 
§ ‘Comptes Rendus,’ Aug. 22, 1864. 
|| ‘Chemical News,’ vol. x. p. 1. 
4 ‘Comptes Rendus,’ July 6, 1864. 
