1870.] 



Deep-sea Researches. 



151 



and another repetition does the like with the third tube. This apparatus, 

 with a deep-sea lead attached to it, is suspended by an insulating cable 

 that contains the wires whereby it is connected with the battery in the 

 vessel. Being lowered down to any desired depth, the circuit is com- 

 pleted, the magnet made, and one of the tubes exposed for as long a time 

 as may be wished ; the circuit is then broken, the magnet unmade, and 

 the tube shut up again. The second tube may be exposed for a longer 

 time in the same place, or the apparatus may be lowered to a greater 

 depth, at which the experiment may be repeated ; and the third tube may 

 then be dealt with in like manner. — The Committee having been satisfied 

 with the performance of Mr. Siemens's apparatus, it had been arranged that 

 trial should be made of it, and also of his Differential Thermometer, now 

 provided with an improved Galvanometer ; and he had undertaken to send 

 out a qualified Assistant to take charge of these instruments during the 

 Mediterranean Cruise. The declaration of war between France and Ger- 

 many, however, unfortunately interfered with this arrangement ; the As- 

 sistant (a German) being recalled to his own country, and no other com- 

 petent person being available on a short notice. Under these circumstances 

 it was thought better that the Differential Thermometer should not be sent 

 out ; but it was hoped that such a trial might be given to the Photometric 

 Apparatus as should at any rate determine whether satisfactory results 

 might be anticipated from its use, or whether any modifications in its con- 

 struction might be needed. The apparatus was sent out to Gibraltar 

 under charge of Dr. Carpenter, and was got into working order by his Son 

 and himself in Gibraltar Harbour. It proved, however, that the action of 

 sea-water on the bearings, — increased as this was by the galvanic current 

 arising out of the contact of iron and brass in them, — so embarrassed its 

 Mechanical arrangements, that no fair trial could be made of its Photo- 

 metric efficiency. But the experiment served the important purpose of 

 showing the weak points of the apparatus ; and neither Mr. Siemens nor 

 Dr. Carpenter entertains any doubt that it may be so reconstructed as to 

 answer the purpose for which it was devised. 



3. The work of this year's Expedition was divided, according to the plan 

 originally marked out, into two Cruises : the first to examine the Deep-sea 

 bottom between Falmouth and Gibraltar ; the second to make the like 

 examination of the western basin of the Mediterranean between Gibraltar 

 and Malta, and to determine its Physical and Biological relations to the 

 Atlantic, with special reference to the Gibraltar Current. — The First 

 Cruise was under the scientific direction of Mr. Gwyn Jeffreys, who was 

 accompanied by a young Swedish Naturalist, Mr. Josua Lindahl, of the 

 University of Lund, as Zoological Assistant ; whilst Mr. W. L. Carpenter, 

 as before, took charge of the Chemical department, — his special work, on 

 this occasion, being the determination, by Volumetric analysis, of the pro- 

 portion of Chlorine in samples of Atlantic water taken from the surface, the 

 bottom, and from intermediate depths, so as to serve as a basis of com- 



