Proceedings of the Royal Institution. 399 



through the Surf. — Capt. Manby this evening gave an account of his 

 methods of casting a line from shore to a ship in distress, either by 

 day or night, illustrating it by his own model of the apparatus used 

 upon the coast. These having been published in various ways, we do 

 not think it necessary to detail here. He then described the me- 

 thod which he has recently suggested, of hauling boats off from 

 shore through the surf, that they may proceed to ships in distress. In 

 cases of storm and shipwreck, the surf is generally so strong as to 

 throw every thing back that tries to make way through it, oars being 

 then found of no avail. Captain Manby proposes that, to meet such 

 cases, an anchor with an attached buoy be carried out beyond the line 

 of surf at low-water, a block made fast to the buoy, so as not to tum» 

 and a rope rove through it, so long as to reach double from the 

 buoy to the shore. Then, in time of need, a boat being fastened to 

 one end of the rope, if the other end be laid hold of, and the rope 

 hauled on, it necessarily carries the boat out to sea. But as, if left 

 to itself at those times when not wanted, but waiting to be used, the 

 rope would probably bury itself in the sand, provision is made against 

 this, by attaching a buoy with a hanging noose to one of the halves 

 of the rope, about half way between the anchor and the shore, and 

 letting tlie other half or end pass through the noose ; in this way the 

 rope is suspended in the water, and retained out of the sand. 



June ith. 



• Mr. Brockedon offered some remarks upon the Perception and 

 Application of Colour. His chief object was to state some curious 

 facts upon ocular spectra, and to excite physiologists to such an exami- 

 nation of the structure of the eye, as might lead to a knowledge of the 

 cause of those remarkable and beautiful effects which, in good vision, 

 are always perceived after excitement by an object of any colour, 

 when the complementary tint appears, or that colour which, combined 

 with the impinging colour of the external object, produces white 

 light The most familiar mode of exhibiting these complementary 

 spectra is, by placing wafers of different colours upon white paper, 

 and, after gazing intently upon any one, suddenly removing it, when 

 a contrary colour, but of the same form, is instantly perceived, and this 

 often even when the eyes are closed. The demonstration of these com- 



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