396 Royal Society. 



of its sense. I had the less hesitation in doing this, as in M. Vogt's 

 subsequently published ' Zoologische Briefe*,' he gives the received 

 interpretation to the parts of the so-called 'hearts' without any in- 

 dication of a change of opinion. 



I make this statement in explanation of what might otherwise 

 seem to be great carelessness on my part, and for the purpose of 

 further pointing out that M. Vogt not having made the supposed 

 discovery, it is quite impossible that Professor Owen's researches 

 should have been suggested by it. 



Feb. 22, 1855.— The Lord Wrottesley, President, in the Chair. 



The following communication was read : — 



" On the Temperature and Density of the Seas between South- 

 ampton and Bombay vid the Mediterranean and Red Seas." By 

 MM. Adolphe, Hermann, and Robert Schlagintweit. 



In this communication the authors give the results of the observa- 

 tions they had made during their voyage, relative to the temperature 

 and specific gravity of the sea-water, both near the surface and at 

 depths ranging from about 18 to '60 metres, the latter being nearly 

 the greatest depth which the motion of the vessel permitted them 

 to reach. They reserve for a future report their observations on the 

 temperature and moisture of the air, as well as the results of two 

 experiments on the quantity of carbonic acid contained in the air on 

 the Mediterranean and Red Seas. 



The instruments employed in the observations here described 

 were as follows : — 



(1.) Four thermometers which had been carefully compared at 

 the Kew Observatory previous to the authors' departure. At Bom- 

 bay they repeated the determination of the zero-point and of an- 

 other standard point, and found that the thermometers had not 

 varied. 



(2.) A dipping apparatus constructed by Mr. Adie. This appa- 

 ratus, which held 5 or 6 litres, was furnished with two valves, so 

 arranged that as it descended the water passed freely through, but 

 as soon as a commencement was made of drawing it up the valves 

 closed and rendered it water-tight. The authors assured themselves 

 that the temperature of the enclosed water did not sensibly change 

 during the process of drawing it up. 



(3.) An areometer from Mr. T. G. Greiner at Berlin. This in- 

 strument permitted the specific gravity to be read off directly to 

 three places of decimals, and the fourth could be supplied by estima- 

 tion. 



To render the observations of specific gravity comparable with one 

 another, it was necessary to reduce them to a common temperature, 

 which occasioned some difficulty, as the exact expansion of sea- 

 water between the limits 20° and 25° C. was not accurately known. 

 Bv means of a delicate voluminometer, constructed for the purpose 

 by M. Geissler of Berlin, the authors determined the expansion to lie 



* Frankfort, 1851, vol. i. p. 285. 



