SCIENTIFIC SUMMARY. 
323 
quantity of pure coffee, an approximate method of examining our mixture 
quantitatively. 
The Reaction of Biliverdin. — This is a subject to which Dr. Thudicum 
has recently been devoting his attention. He read a paper upon it at the 
meeting of the Chemical Society on May 4. After stating that the cause 
of the yellow colour of the skin of persons suffering from u yellow jaund- 
dice ” was bilirubin, whilst the dark colour of the so-called 11 black jaundice” 
was due to the presence of biliverdin, he proceeded to describe some deri- 
vatives of the latter substance. Monobrominated biliverdin, C 8 H 8 BrN0 2 , was 
prepared by passing bromine vapour mixed with dry air over finely powdered 
biliverdin until it ceased to be absorbed, and the product was then heated 
to 100°C. in a current of dry air. It is a black powder, insoluble in ether, 
and very little soluble in alcohol. It is soluble in sulphuric acid, but is pre- 
cipitated on dilution with water. It is soluble in caustic soda, being preci- 
pitated again in brown flocks by acetic acid. ELydro-biliverdin is formed on 
treating a solution of biliverdin in dilute caustic soda with sodium amalgam. 
It dilutes alcoholic solution, gives a spectrum showing an absorption-band 
overlying the line F equilaterally, and totally different from the broad band 
between E and F shown by solutions of hydro-bilirubin. We are not 
quite prepared to accept Dr. Thudicum’s views as to the pathology of the 
disease. 
TJie Manufacture of Sulphuric Anhydride. — A paper on this important 
practical subject was read by Dr. W. Squire before the Chemical Society 
on April 20. Dr. Squire, after giving a sketch of the history of the manu- 
facture of sulphuric acid, described the process for preparing the anhy- 
dride. The vapour of ordinary sulphuric acid is passed through a white-hot 
platinum tube, whereby it is almost completely decomposed into water, 
oxygen, and sulphurous anhydride : the mixed gases, after passing through a 
leaden worm to condense the greater portion of the water, are completely 
dehydrated in a leaden tower filled with coke, over which a stream of con- 
centrated sulphuric acid is allowed to trickle. The dry mixture of oxygen 
and sulphurous anhydride is now passed through platinum tubes heated to 
low redness, and containing fragments of platinised pumice, when the gases 
recombine to form sulphuric anhydride, which is condensed in a series of 
Woulffe’s bottles. 
Experiments on the Sugar Beet have been lately carried out by MM. 
Fremy and Deherain, which show (Comptes rendus, April 24) that saline 
solutions identical in composition act very differently upon beets according^ 
as the roots plunge into the solutions themselves, or as the latter merely 
occupy the pores of the soil. On planting beets of different origin in iden- 
tical conditions as to soil, manure, and watering, roots are obtained differing 
in their yield of sugar. An excess of nitrogenous manure lowers the per- 
centage of sugar in all beets, but those of a superior strain preserve still 
such a quantity of sugar that they may be advantageously treated. To 
produce from a given surface the maximum of sugar under conditions advan- 
tageous alike for grower and manufacturer, we must depend above all on a 
judicious selection of the seed. 
Calcareous Alabaster from Mexico. — M. A. Damour says, in a paper 
read before the French Academy, on May 8, and quoted by the “ Chemical 
