22 AXXUAL OF SCIENTIFIC DISCOVERY. 



at that velocity with a given power. Further: the resistance which n vessel 

 experiences from the sticking of water to the skin was a most formidable 

 element of her whole resistance; and greater velocity in proportion to power 

 would be got out of a vessel which was shorter than another, and also 

 broader and deeper than another, providing length enough for the velocity 

 aimed at were got at starting. 



It was the duty of the author, however, to say a word or two on the his- 

 tory of the subject, and the degree of novelty or non-novelty to which it 

 pretended. And he began with saying that he did not claim to be the in- 

 ventor of hollow bows. They had existed as far back as he could trace 

 steam navigation. When he had first discovered what he believed to be the 

 principles of nature which bore on this subject, he felt that the form of ves- 

 sel which accorded with them could not be new, and he set about examining 

 all classes of vessels. He found proofs immediately; so many, that he felt 

 astonished that the books and treatises on naval architecture had not all told 

 them to do nothing but make hollow bows from the beginning. He showed 

 that it must have been impossible for barbarous men to have made a rough 

 boat from two flat planks without forming such a bow. But the old tonnage 

 laws had compelled builders to make ships of the greatest possible capacity 

 compatible with certain measurements. Hence the bluff bow was made a 

 matter of necessity. When, during the wars, we captured Spanish ships or 

 privateers with fine and often hollow lines below, vessels which sailed 

 admirably under their original trim, in which they were down by the stern, 

 we invariably found that they proved but dull sailers in our hands, owing 

 undoubtedly to the fact that we not only overloaded them with weights, but 

 trimmed them nearer to an even keel, and so brought the bluff upper part 

 of their bows down into the water. The boats of the London watermen 

 illustrated the same principle. 



The author concluded by stating that the rapid advancement of confidence 

 in the wave principle was owing very much to the British Association for 

 the Advancement of Science, which had placed at his disposal large means 

 for the prosecution of scientific researches into this subject, and had every 

 year enabled him to publish to the world the progress which he was making 

 in the investigation. 



NEW METHOD OF CLEANING THE BOTTOMS OF IRON VESSELS. 



A new and novel method of cleaning the bottoms of iron vessels has been 

 successfully put in operation by Captain R. P. Dyker, of New York City. 

 The apparatus consists of blocks, each formed of three pieces of cork-wood 

 and one of white-wood, firmly bolted together. On the piece of white- 

 wood are fastened nine knives, or scrapers, six of which run parallel with 

 the line of the vessel, and the remaining three are placed at right angles 

 with the others. Ropes pass through these blocks, which latter may be so 

 arranged as to be of any required length. To lengthen them it is only ne- 

 cessary to shackle on others. The block that comes in contact with the keel 

 is much thicker than the others, so that it may reach that portion of the 

 bottom which the thinner blocks would not. The blocks of course vary 

 with the depth of keel of the vessel which is to be cleaned. 



The operation of cleaning an iron brig of about two hundred tons is thus 

 described by the New York Cominr-rcutl Advertiser: The apparatus con- 

 sisted of seven blocks, of eighteen inches in length, ten inches wide, and 



