1869.] 



on the Scientific Exploration of the Deep Sea. 



403 



mittee were unwilling to risk the loss of a somewhat costly instrument in 

 case the cable were to break. On these accounts they thought it best to 

 adopt the simpler plan proposed by Mr. Siemens ; and the apparatus re- 

 quired for carrying the plan into execution is now completed, and in use in 

 the expedition. 



" Meanwhile a plan had been devised by Dr. Miller for obviating the 

 effect of pressure on a minimum thermometer, without preventing access 

 to the stem for the purpose of setting the index. It consists in enclosing 

 the bulb in an outer bulb rivetted-on a little way up the stem, the interval 

 between the bulbs being partly filled with liquid, for the sake of quicker 

 conduction. The Committee have had a few minimum thermometers con- 

 structed on this principle, which have been found to answer perfectly. The 

 method is described in a short paper which will be read to the Society 

 to-morrow. 



" For obtaining specimens of water from any depth to which the dred- 

 ging extends, the Committee have procured an instrument constructed as 

 to its leading features on the plan of that described by Dr. Marcet in the 

 Philosophical Transactions for 1819, and used successfully in the earlier 

 northern expeditions. 



" Mr. Gwyn Jeffreys is now out on the first cruise of the 'Porcupine/ 

 the vessel which the Admiralty have sent out for the purpose, and is 

 accompanied by Mr. W. L. Carpenter, B.Sc. (son of Dr. Carpenter), who 

 undertakes the general execution of the physical and chemical part of the 

 inquiry. A letter has been received by the President from Mr. Jeffreys, 

 who speaks highly of the zeal and efficiency of Mr. Carpenter. The ther- 

 mometers protected according to Dr. Miller's plan, and the instrument for 

 obtaining specimens of water from great depths, have been found to work 

 satisfactorily in actual practice. Mr. Siemens' s instrument was not quite 

 ready when the vessel started on her first cruise, and was not on board 

 when the above letter was written. The gas-analyses have been success- 

 fully carried on, notwithstanding the motion of the vessel. From a letter 

 subsequently received from Mr. Carpenter, it appears that Mr. Siemens's 

 apparatus, so far as it has as yet been tried, works in perfect harmony 

 with the thermometers protected according to Dr. Miller's plan." 



"June 16, 1869." 



Resolved, — That the Report now read be received and entered on the Mi- 

 nutes. 



Equipment. 



1 . The equipment of the c Porcupine' for the purposes of Deep-sea Sound- 

 ing and Dredging was devised on the basis of the experience gained in 

 previous Deep-sea Sounding Voyages (especially in that of the ' Hydra'*), 



* Sounding Voyage of H.M.S. ' Hydra,' Captain P. R. Shortland, 1868; also Notes 

 on Deep-Sea Soundings, by Staff-Coramander Davis, 1867. 



