186 Capt. Belavenetz on the Magnetic Character [April 27, 



in exact proportion as our observation of them has become more exact, 

 until at last it has been compelled to take refuge in those lowest forms 

 which we are almost or altogether unable to observe, is really of little or 

 no force. Its cogency depends on analogy, and the analogy has no 

 existence. It is quite equally to be expected ct priori that if any forms of 

 life are generated spontaneously, they will be the very lowest and simplest 

 forms, and since these happen to be also the most minute, the objection 

 loses its whole force. And it is also a thing to be expected that we should 

 find only the lowest forms, the earliest, i. e. in the scale of existence, produced 

 under the disadvantageous circumstances in which they must be placed in 

 such experiments as those above detailed. 



The other remark is this, that, so far as my present researches have led 

 me, I cannot but look upon improvement in the construction of micro- 

 scopes, and increase of their power, as the only way in which our means of 

 investigation of such questions as the production of Bacterium is likely to 

 be largely increased. The -^ object-glass recently constructed by Messrs. 

 Powell and Lealand, of which a notice has appeared in the Proceedings of 

 the Royal Society, has already shown something like an appearance of 

 structure in these minute objects, and leaves, I think, no doubt about 

 their organic character. 



II. "On the Magnetic Character of the Iron-built Armour-plated 

 Battery 'Pervenetz' of the Imperial Russian Navy." By 

 Capt. J. BELAVENETZ, R.I.N., Superintendent of the Compass 

 Observatory at St Petersburg. Communicated by ARCHIBALD 

 SMITH, M.A., Corresponding Member of the Scientific Com- 

 mittee of the Imperial Russian Navy. Received March 23, 1865. 



1. The 'Pervenetz' is an iron-built armour-plated ship of war, con- 

 structed for the Russian Government by the Thames Iron and Ship- 

 Building Company at their works at Blackwall. 



2. The following are her dimensions : 



Length 220 feet 



Breadth 53 feet 



Depth of hold 26-6 feet 



Builder's measurement 2393 tons 



Horse-power 300 



3. The upper and main decks were plated with sheet iron. 



4. The greater part of the side plating was fixed in England and while 

 the observations recorded in the paper were made, but no part of the end 

 plating was fixed, the plates being taken on board and carried as cargo. 



The direction of her head in building was S. 22 I/' W. magnetic. 



5. The author was commissioned by the Russian Government to super- 

 intend the compass equipment and compass correction of the ship. He 



