Temperature and Density of Mediterranean 125 



when examined with a hand lens, more than could be seen 

 by the unaided eye. He went on to speak of the binocular 

 microscope, 1 saying that a defect in the original instrument 

 had now been overcome by Nachet, a French optician. 

 With the latter he had examined Polycystinae from Barbados, 

 using a J-inch objective, with admirable results. 



According to Colonel Sykes, Mr. Bonelli, superintendent 

 of the electric telegraph at (?) Sidmouth, had devised a plan 

 for replacing the card process in the Jacquard loom by a 

 telegraphic apparatus which, he maintained, would reduce 

 the cost of working that loom by two-fifths. 



Oct. 26th. 68th meeting. Mr. Wheatstone described 

 a ' difference engine,' 2 invented by M. Schwarz, then on 

 view at Bermondsey, and exhibited tables calculated and 

 printed by it. 



Mr. Rennie suggested a plan for closing the southern 

 channel of the Bay of Cronstadt (not more than 8 feet deep) 

 by sinking ships across it, which would cause it to be silted up. 



At the 6gth meeting (Nov. 23rd) Colonel Sykes read a letter 

 from the Messrs. Schlagintweit, dated ' off Alexandria/ and 

 giving the general results of their examination of the tem- 

 perature and density of the water in the Mediterranean, 

 which they had taken several times daily. Their observa- 

 tions showed that, in proceeding eastwards, the specific 

 gravity increased. 3 A discussion followed on the methods 

 of bringing water from great depths, and on some recent 

 analyses of such water. 



Sir Proby Cautley gave an account of the difficulties 

 encountered in the construction of the Ganges Canal, lately 



1 It was devised in 1851 by Professor J. L. Riddell, of New Orleans, and 

 constructed in the following year. See The Microscope and its Revelations, 

 by W. B. Carpenter (Ed. Dallinger, page 97). 



2 The elaborate calculating machine, at which C. Babbage worked from 

 1822 to 1842, was given up in the latter year. One which was a greater 

 practical success, and is still used, was produced by M. Thomas, of Colmar, 

 about 1850. 



8 The temperatures of the western part of the Mediterranean are noticed, 

 after more systematic soundings, in Wyville Thomson, Depths of the Sea, 

 ch. vii., and that of the Ocean in his Voyage of the Challenger (the Atlantic), 

 and in certain of the special Reports of that expedition. 



