438 Mr. Dick on a Spiral Oar. [June, 



possessing acid qualities." At his request, Mr. Faraday endea- 

 voured to obtain it, by causing a mixture of the vapour of ether 

 and common air to traverse a heated glass tube containing pieces 

 of platina wire and foil, and terminating in a bottle placed in a 

 freezing mixture. The quantity thus obtained, even after the 

 process had been continued several hours, was so small as to 

 induce Mr. Faraday to conclude, that " until some other process 

 has been discovered for producing it, there is little hope of its 

 being obtained in its pure state." * With the lamp I found no 

 difficulty in collecting from the slow combustion of sulphuric 

 ether a transparent, perfectly colourless fluid, of a penetrating 

 odour, and peculiarly pungent acid taste. It may be procured 

 in any quantity by placing over an ignited lamp, filled with 

 ether, the head of a small glass alembic with the lip turned up 

 inward, and regulating the admission of air at bottom, so that in 

 the dark there may appear a Cone of faint blue light issuing from 

 the coil, while the wire itself seems scarcely ignited. To assist 

 condensation, the upper portion of the alembic-head may be 

 covered with bilulous paper, kept moist by the ends of some soft 

 cotton threads resting on it, whose other extremities are 

 immersed in cold water. Thus circumstanced, the fluid produced 

 by the slow combustion of the ether will, after the process, be 

 found collected in the lip of the alembic-head. 



I am, Gentlemen, your very obedient servant, 



Francis Ellis. 



Article X. 

 On a Spiral Oar. By T. L. Dick, Esq. F.R.S.E. 

 (To Dr. Thomson.) 



SIR, Relugas, near Forres, April 8, 1818. 



When I was lately in East Lothian, my friend Mr. Scott, of 

 Ormiston, put some drawings into my hands, illustrative of an 

 old project of his, for applying certain combinations of machinery 

 to vessels of war, in order to enable them to sink the boats form- 

 ing the flotilla of an invading enemy. These were likewise 

 accompanied by explanatory manuscript observations. Were I 

 to lay his paper before your readers at full length, I am con- 

 vinced they would be gratified by the ingenuity it displays. But 

 as we are now enjoying the propitious dawn of what we trust 

 will be a long period of peace, and as the detail of such destruc- 

 tive inventions can now have no effect but to awaken harsh and 



» JEiperiments, &c. on a new acid substance — Journal of Science, No. V. 



