>gQ katureAnd decomposition of the fixed ALKAIIS* 



common cannon ; the collar slides along it in the same man- 

 ner as that in fig. 4, to allow the head of the pin to go 

 down to the wadding within the cannon ; i i, are two pins 

 on which the ring k is movable ; /, the blork or pulley fas- 

 tened to the ring ; m, the endless or double line running 

 through it. 



This method may be used with great advantage, where a 

 ship is stranded neav the shore ; but where a movtar is on 

 board, the use of the shell and line is the most certain. 



Fig. 6 Shows the method of forming a raft, by lashing 

 together with ropes five empty water casks belonging to the 

 ship. 



Fig. 7. Represents the^ raft ready for use ; the apparatus 

 n, to hold the person upon it, is made from a seaman's chest 

 with holes cut in the sides of it, to allow the person within 

 it firmer hold, and to let out the water that may be thrown 

 into it from the waves; are two pulleys attached to the 

 ends of the chest, and through which the line is to run ; 

 the raft is to be ballasted underneath, to prevent it from 

 upsetting. 



The whole apparatus is so arranged as to be enclosed in a 

 small box, as may be seen by a reference to that in the So- 

 ciety's possession. 



T/ie Bakerian Lectuj^e, on some neiv Phenomena of chemical 

 Chavges produced by Eleciricity, particularly the De- 

 composition of the Jixed Alkalis, and the Exhibition of 

 the new Substances which constitute their Bases; and on 

 the general Nature of alkaline Bodies. By Humphrt 

 Davy, Esq. Sec. R. S. M. R. I. A. * 



Read November 19, 1807. 



I. Introduction. 



Electricity pre- ][ N the Bakerian Lecture which I had the honour of pre- 

 of extendiug senting to the Royal Society last year, I described a num" 



• Philos, TrJiPS. for 180S, Part I, p. 1. ' 



bev 



