SCIENTIFIC SUMMARY. 
313 
Determining Carbonic Add in Sea-water . — Professor Himly, at tlie meeting 
of the Chemical Society, April 18, after pointing out the difficulties which 
beset the determination of carbonic acid in sea-water — Jacobsen having 
shown that the whole of the gas present is not given off by boiling, either 
in vacuo or under the ordinary pressure at 100°, even when a current of air 
is passed through the liquid — said, however, that the whole of the carbonic 
acid could be readily estimated by adding baryta water or barium nitrate, 
ammonium nitrate, and ammonia, to a measured quantity of the sea-water, 
thus obtaining the whole of the carbonic acid in the precipitate. After the 
supernatant liquid had been removed, the carbonic acid might be estimated 
in the precipitate. In order to collect sea- water for the determination of 
the carbonic acid at great depths, and consequently under great pressures, 
it was necessary to sink a cylinder open at both ends to the place where the 
water was to be collected, and then to securely close it there. The apparatus 
for that purpose, closed by valves, had been found to be very defective ; but 
he had employed one which answered admirably, consisting of a cylinder 
furnished with a large stop-cock at each end. When this cylinder had been 
sunk to the required depth, the stop-cocks were closed by powerful springs 
released at the proper moment by means of an electro-magnet set in action 
in the usual way. (See also “ Chemical News.”) 
A New Organic Pigment has been obtained from a spot above the eyes 
of the moor-cock. It is called Tetronerythrin , and has been described by 
Dr. Wurm in “ Poggendorff ’s Annalen.” It seems [“Chemical News”] 
that a statement was made in the “ Wiener Jagdzeitung” to the effect that 
the red warty spot met with above the eyes of the mountain-cock and moor- 
cock ( Tetrao tetrix), when rubbed with a white handkerchief, imparted 
thereto a beautiful red colour. The author was inclined to disbelieve this, 
and accordingly made some microscopical and microchemical researches on 
this subject, the result being that he discovered a pigment which he terms 
Tetronerythrin (from Tetraon and erythros, mountain-cock red). A very small 
quantity of this pigment, which is soluble in chloroform, was sent by the 
author to Dr. J. von Liebig, who states that it is a peculiar substance which 
has nothing in common with the colouring matter of the blood ; it is soluble 
in ether and sulphide of carbon, not soluble in cold caustic alkaline solutions, 
and soluble in hot nitric acid, but decomposed simultaneously, leaving a 
waxy residue. 
Ho to to Know Fruit-wine from Grape-wine. — According to Dr. F. Vor- 
werk [“Neues Jahrbuch fiir Pharmacie ”], the phosphoric acid present in 
genuine grape-wine is combined with magnesia, while in fruit-wines it is 
present in combination with lime. The simple addition, therefore, of am- 
monia (1 part to 9 parts of wine), will produce in genuine wine, after twelve 
hours’ standing, the well-known precipitate of ammonio-phosphate of mag- 
nesia. 
Dr. Letheby and Dr. Frankland on Water-analysis. — The editor of the 
11 Chemical News ” has quite recently given a leading article on this im- 
portant subject. Deferring to the controversy which has come up upon the 
matter, he states that if it had arisen in France there would have been a 
commission of the Academy to report on it. In this country we manage 
things differently, and resolve questions of this description after our own 
