SCIENTIFIC SUMMARY. 
203 
Gallic Acid converted into Tannin. — Herr Lowe has stated that an aqueous 
solution of gallic acid is converted into tannin by the addition of nitrate of 
silver. 
Testing the Purity of Flour. — M. Eakowitsch has recently proposed a 
simple mode of examining flour by means of chloroform. He alleges that in 
the course of a few minutes the following results may be obtained: — The 
amounts of bran, the moisture between 10 and 25 per cent., the damaged 
flom*, the mineral matters, the ergot of rye, and other impurities. The 
whole of these are determined by the relative specific gravities of the different 
substances in chloroform. The flour is simply placed in a tube and mixed 
with chloroform j the chloroform is enabled to hold in very thorough sus- 
pension the pure flour, while the other materials are not thus suspended. 
By adding spirits of wine of 95°, the flour is precipitated to the bottom of the 
tube. The more humid the flour, the more spirits of wine must be added, 
and thus the amount of humidity in the flour is arrived at. — See Foreign 
Correspondence” of Chemical Neivs, March 13. 
The Volumetric Peterminotion of Acetic Acid by means of a standard solu- 
tion of hydrate of soda is rendered difficult by the fact that the acetate of 
soda gives a violet tint to the litmus paper, and thus prevents the chemist 
knowing the exact moment of neutralisation. This difficulty is completely 
obviated by employing tincture of curcuma as a test. In the presence of 
free acid it remains yellow, but it turns brown immediately the acid has 
been neutralised. 
GEOLOGY AND PALAEONTOLOGY. 
Prohlems for Devonian Geologists. — The address of the President, Mr. W. 
Pengelly, in the last volume of the Transactions of the Devon Association, 
is most interesting and suggestive : but it has an especial importance, be- 
cause it points out the subjects which local geologists may study with 
advantage to science. Mr. Pengelly puts the following queries : What is 
the age of the crystalline schists at the southern angle of our county ? 
What is the precise chronology of our limestones and associated rocks ? Is 
there, east of Exmouth, a break in the red rocks ? Whence came the Bud- 
leigh Salterton pebbles ? Whence also the porphyritic trap nodules so abun- 
dant in the trias ? Are our greensands really of the age of the gault ? 
Whence the flints so numerous on our existing beaches ? What is the 
history of our superficial gravels ? Are there any indications of glaciation 
in Devonshire ? To what race did our cave-men belong ? The solution of, 
at least, many of these questions must be reserved for another generation of 
enquirers ; and to the young men of the present day I earnestly commend 
them.” We wish other local Presidents would adopt this plan of directing 
the labours of the provincial geologists. 
The Wollaston Gold Medal and Donation Fund were awarded at the 
Meeting of the Geological Society on Feb. 21st. The gold medal has been 
given to Dr. Carl Friedrich Naumann, Foreign Member of the Geological 
Society, Professor of Geology and Mineralogy in the University of Leipzig, 
&c.^ in recognition of his labours, extending over nearly half a century, in the 
VOL. YII. — NO. XXYII. P 
