Mechanical Science, 33$ 



the orlop-deck to the hold, another decrement of 0*09 \ and from 

 the mean intensity of the hold to the single intensity determined 

 on the kelson, an increment of 14-63. Hence it appears, that 

 the greatest mean intensities are found at the extremes of 

 the series ; that the mean results of the quarter-deck and fore- 

 castle, and main and lower decks, are very nearly the same ; as 

 are also those of the orlop-deck and hold. The mean intensity 

 of the middle-deck is also very nearly a mean, between the mean 

 of the intensities of the three first mentioned decks and of the 

 two latter. The mean of the decks, from the poop to the middle- 

 deck inclusive, is 98"71 ; and of the lower and orlop-decks, hold, 

 and kelson, 97*84. The mean of all the decks is 98-28, being 

 1*72 less than the assumed terrestrial intensity. 



As a useful practical remark, Mr. Harvey observes, since some 

 difference of opinion has existed on the subject, that during his 

 experiments it has appeared, that the changes and diversities of 

 intensity on board small ships of war are more considerable than 

 those which take place in vessels of a larger class. 



8. Naval Architecture. — In our Number for January last, we 

 inserted a long and elaborate article on the Comparative Means 

 of Defence afforded by Ships with Square and Curvilineal Sterns ; 

 a subject of great interest to our naval readers, and one on which 

 we know they are desirous of having as much light thrown as 

 possible. With this view we present them with an Abstract of a 

 Paper published by the same author, in the second Number of 

 the Edinburgh Journal of Science. 



Mr. Harvey, the author of the papers alluded to, remarks, 

 " that it may not be generally known that the application of cir- 

 cular sterns to ships of war forms a necessary and important part 

 of the improved system of ship-building, latterly introduced into 

 the public service by Sir Robert Seppings ; and that, without the 

 full and perfect application of it to ships of all classes, this ex- 

 cellent system will be rendered, in a considerable degree, ineffec- 

 tual. Indeed, the necessary and essential connexion between 

 the diagonal trussed frame, the shelf-pieces and thick water- 

 ways, and their peculiar adaptation to the form of the circular 

 stem, renders it impossible to separate either from the new sys- 

 tem of ship-building, without producing a most important injury 

 to the public service." 



Mr. Harvey again observes, ** the general and unexceptionable 

 merits of the diagonal system are now universally acknowledged ; 

 but the advantages resulting from the shelf-pieces and thick wa- 

 ter-ways, and the admirable mode by which the beams are con- 

 nected to them, by means of coaks and bolts passing through the 

 whole, although clearly understood by those well-informed men 

 who have turned their attention to the inquiry, have, neverthe- 



