Mr. NAPIER on Water-tiylil Compartments in Iron Vessels. 289 



portion as possible, of the oscillating electricity may remain in it and not 

 give rise to successive sparks across the space of air separating the dis- 

 charger from the source of the electricity. 



The paper is concluded with applications of the results to determine 

 the laws, according to which a current varies at the commencement and 

 end of any period, during which a constant electro-motive force, such 

 as that of a galvanic battery, acts in a conductor of given electro-dynamic 

 capacity and resistance, and to show how the relation between the electro- 

 statical and electro-dynamic units of electrical quantity and electro-motive 

 force may be experimentally determined. 



February % 1853. — The President in the Chair. 



Mr. Donaldson and Mr. Taylor were admitted as members. 



Mr. Malcolm M'Niel Walker, optician, was proposed a member by 

 Mr. James R. Napier, Mr. W. M. Buchanan, and Mr. Charles Griffin. 



Papers were read by Mr. James R. Napier, " On the Bulk-heads and 

 Water-tight Compartments of Steam-vessels." 



"Experiments on the Evaporation of Water in Copper, Iron, and 

 Lead Vessels." 



" Experiments on the Compasses of Iron Vessels." 



XXXVII. — Illustrations of the Utility of Water-tight Compartments in 

 Iron Vessels. By Mr. J. R. Napier. 



Iron steam-vessels are obliged by Act of Parliament to have three 

 water-tight compartments, which is usually done by placing one bulk- 

 head before the machinerj- and one abaft it. 



It is well known that many accidents have happened to vessels, which 

 would in all probability have been fatal, or attended with very serious 

 loss, but for the timely assistance of one or other of these compartments. 



The " Fire Queen," for instance, a small screw vessel, originally built 

 as a pleasure yacht for Mr. Assheton Smith, was in 1850 placed as a 

 goods and passenger vessel upon the Glasgow, Ardrossan, and Ayr 

 station. One afternoon, at low water, on leaving Ardrossan harbour, she 

 struck the fluke of an anchor a few feet before one of the water-tight 

 bulkheads; the fore compartment filled with water, and the bow sank to 

 the bottom. The middle and after compartments, however, kept her from 

 entirely .sinking, as the tide rose they floated her to the shore, where the 

 cargo was discharged without damage, and the hole being temporarily 

 stopped, the vessel steamed to Glasgow next day for repairs. 



The late " Metropolitan," screw steamer, also on one of her passages 

 from London to Glasgow, struck a sailing ship in the Bristol Channel. 

 The ship sank in about ten minutes afterwards, and although the fore- 

 most compartment of the steamer was filled with water, she proceeded on 



