210 
POPULAK SCIENCE KEYIEW. 
chemists or not — are interested in, has been very exhaustively dealt with in 
a paper read before the Chemical Society of London, at a recent meeting, by 
Mr. J. Bell, of the Laboratory at Somerset House. He says that tea is 
adulterated to a very large extent, not only with leaves of various kinds, 
including exhausted tea-leaves, but also with inorganic substances, such as 
quartz, sand, and magnetic oxide of iron ; these latter substances are rolled 
up inside the leaf, and one sample of green tea examined was found to con- 
tain no less than 20 per cent, of quartz and 8'6 of the magnetic oxide. The 
latter may readily be separated by grinding up the tea, and removing the 
magnetic oxide with a magnet. The facing employed for green tea usually 
consists of French chalk and Prussian blue. In the preparation of exhausted 
tea-leaves, they are rolled up with gum-water, and then dried, catechu 
being added in some cases to restore the astringency. The article known as 
the u maloo mixture ” consists essentially of exhausted tea-leaves. In 
searching for the presence of other leaves than those of the tea-plant the 
best method is to heat a small quantity of the suspected tea with water 
until the leaves are sufficiently softened to admit of being unfolded. They 
should then be spread out on a piece of glass, and carefully examined as to 
the nature of the serratures and the character of the venation, also the form 
of the cells of the epidermis and the stomata, and the peculiarities of the 
hairs as shown by the microscope. The essential differences which the tea- 
leaf presents when compared with other leaves were minutely described. 
The chemical composition of tea was next discussed, the amount of lignin 
and of tannin being very important. 
Absence of Italian Chemists. — At a congress of Italian savants , which 
held a recent sitting at Rome, a meeting of the Chemical Section, under 
the presidency of Professor Cannizzaro, undertook a discussion on the rarity 
of original chemical research in Italy, and on its causes. The Section was 
of opinion that to awaken activity in this department it is desirable that the 
profession of chemistry should offer to students a career analogous to that 
presented by engineering or by medicine. To this the u Chemical News ” 
adds ; u A similar complaint and a similar suggestion might be made in Eng- 
land, with the additional complaint that engineers and medical men are 
continually encroaching upon the sphere of the professional chemist.” 
M. Paul's Improvement in Photo-Lithography. — According to the u Che- 
mical News ” of February 13, 1874, M. Paul produces a positive image on 
paper covered with a layer of albumen mixed with a concentrated solution 
of bichromate of potash. After a sufficient insulation under the negative, 
the paper is covered with lithographic ink, and then immersed in cold water 
to dissolve the unaltered albumen. 
GEOLOGY AND PALAEONTOLOGY. 
New Facts on the Relations between Reptiles and Birds. — Our headers will 
remember that some years ago we gave the only illustrated paper which 
had appeared on this subject, by Professor Huxley. Now Mr. H. Woodward, 
F.R.S., has come before the Geological Society, to offer additional remarks 
