Mr. De la Fons on Mooring Ships. 289 



wreen glass tube, still gave out arsenious acid, which sub- 

 Umed and crystallized as in the former case ; the quantity was 

 however small, and the rest of the mineral fuzed at a red heat 

 into a substance which, when cold, was brittle, gray, and by 

 examination proved to consist of copper and arsenic, in com- 

 bination with a small quantity of sulphur, and a trace of iron. 

 I have no doubt that the gray metallic hard substance is an 

 arseniuret of copper, but the difficulty of separating it perfectly 

 from the accompanying bodies will interfere with an accurate 

 determination of its composition. 



XLVII. Remarks on Col. Miller's Plan for Mooring Ships in 

 Roadsteads. By Mr. J. P. De la Fons. 



To the Editors of the Philosophical Magazine and Annals. 



Gentlemen, 



BEING the patentee of a most material improvement in 

 moorings, which invention is also applicable to other 

 valuable purposes, I embrace as early an opportunity as oc- 

 curs to me, for offering a few remarks upon a communication 

 on the subject of moorings, which appeared in your Journal 

 for August last. 



That a mooring upon principles of perfect security is much 

 wanted for the use of the merchant-service, no one acquainted 

 with the subject can dispute. Whoever has witnessed the hor- 

 rors of a shipwreck, which in the majority of cases originates 

 in a defective anchorage must regret that nothing has yet 

 been successfully attempted for the purpose of averting so 

 frightful a calamity. In the hopes of attaining so desirable 

 an object, various methods have been suggested, similar in 

 prmciple to the one in question ; some of which have been 

 tried, but, as might be expected, they have failed at the very 

 time when security was of the utmost importance. Nor can it 

 be wondered at, when we consider that in lieu of the anchor, 

 which, although it takes hold of the ground, is so liable to fail, 

 a mass of iron depending upon its weight alone has been sub- 

 stituted, and with as probable a chance of success as if the 

 aeronaut were to dispense with his grapples, and in the expec- 

 tation of arresting its progress, attach his balloon to a weight 

 that was inadequate to the resistance of so large a body driving 

 before the wind. 



Your correspondent's plan so far differs, that he proposes 

 ill some cases to fasten it, with pegs driven around it, into the 

 ground by means of the diving-bell, which (the bell not being 

 large enough to contain powerful machinery) 1 conclude he 

 purposes doing by manual hibour: but 1 apprehend any at- 

 New Series. Vol. 2. No. 10. Oct. 1827. 2 I' tempt 



