40 Sketch of the latest Improvemenis [Jan. 



It is not easy to say what kind is meant by the name of English 

 potatoe. There are many varieties in England, differing very much 

 in their properties. In general the potatoes raised in the north of 

 England are better than those raised in the south ; though to this 

 rule there m^y be exceptions. 



XI. Animal Substances. 



Dr. Gordon's experiments showing the evolution of heat during 

 the coagulation of the blood [Amiais of P hilosophy , iv. 131),) con- 

 stitute a pleasing fact, because they confirm the general law of the 

 evolution of heat when bodies change from a liquid to a solid form. 

 Dr. Front's farther experiments on the quantity of carbonic acid 

 evolved by respiration at different times of the day, and as affected 

 by various circumstances, and the confirmation they have received 

 from the recent experiments of Dr. Fife, are deserving of the 

 attention of physiologists, and are well calculated to throw addi- 

 tional light on this still mysterious function, so essential to life, that 

 it cannot be interrupted ; yet, as far as we can find, serving merely 

 to remove a little carbon from the blood. 



1. Air in the Swimming Bladders of Fishes. — All chemical 

 readers are acquainted with Biot's experiments to determine the 

 composition of the air in the swimming bladders of fishes, published 

 in the Memoirs d'Arcueil, and with the unexpected result that the 

 proportion of oxygen in these bladders increases with the depth at 

 which the fish live. Since the publication of that paper an elabo- 

 rate set of experiments on the same subject has been published by 

 Configliachi, an Italian Professor. He has confirmed and extended 

 the facts ascertained by his predecessors. One of the most curious 

 parts of his paper is a table of the proportion of oxygen gas found 

 by him in sea-water of different depths. The following is a copy 

 .of that table : — 



Depth in Metres. Proportion of Oxygen, 



50 28-7 



100 28-8 



150 28-5 



200 27-9 



250 28-4 



300 28-7 



350 29-0 



400 28-5 



450 27-8 



500 28-1 



550 28-4 



600 28-3 



650 28-3 



7C0 28-2 



2. Urine. — Professor Wurzer lias published a set of experiments 



1 



