CHAP. Hi.] THI CRUISES OF THE 'PORCUPINE: 139 



for the purpose of investigating the bottom of the Ocean by 

 means of deep-sea soundings, will be entertained whilst embarked 

 on board the ' Porcupine ' at the Government expense. 



" I am, Sir, 

 Your obedient servant, 



"W. G. EOMAINE." 

 " The President of the Royal Society." 



June 17, 1869. 



Eead the following Eeport : 



"The Committee appointed Feb. 18, 1869, to consider the 

 Scientific Apparatus it will be desirable to provide for the pro- 

 posed Expedition for Marine Eesearches, beg leave to lay before 

 the Council the following Eeport : 



"The chief subjects of Physical Enquiry which presented 

 themselves as interesting on their own account, or in relation to 

 the existence of Life at great depths, were as follows : 



"(1) The temperature both at the bottom and at various 

 depths between that and the surface. 



"(2) The nature and amount of the dissolved Gases. 



" (3) The amount of Organic matter contained in the water, 

 and the nature and amount of the Inorganic salts. 



" (4) The amount of Light to be found at great depths. 



"Among these subjects tjie Committee thought it desirable to 

 confine themselves in the first instance to such as had previously 

 to some extent been taken in hand, or could pretty certainly be 

 carried out. 



" The determination of Temperatures has hitherto rested 

 chiefly upon the registration of minimum Thermometers. It is 

 obvious that the temperature registered by minimum thermo- 

 meters sunk to the bottom of the sea, even if their registration 

 were unaffected by the pressure, would only give the lowest 

 temperature reached somewhere between top and bottom, not 

 necessarily at the bottom itself. The temperatures at various 

 depths might indeed, provided they nowhere increased on going 

 deeper, be determined by a series of minimum thermometers 

 placed at different distances along the line, though this would 



