39 2

HISTORY OF MARINE ARCHITECTURE.

to 7.21 2 t and augments the motive power to 49.28. Fig. m, cannot be said topossess a fore-body, being composed of the central cube only ; which has hi-therto, both in size and in form, been invariably adopted through the whole ofthe experiments : and an after-body, of the same size and form with those usedin all the experiments, from d to ^inclusive. Its rate is rapidly decreased to 5.742,and the necessary motive weight augmented to 155.97. Fig. n differs from theformer, in nothing but the elongation of the after-body, which is of the samelength with that of /: the rate of passage is still farther lessened to 5.697; butthe motive weight, by a still farther apparent cross in the experiment, is diminished,though very immaterially, to 155*78.

Fig. a,

fore-body; a point that may easily be discovered, for, as is very properly observed, it relates to mereresistance only. “ But,” proceed the gentlemen who have made the report m question, “ it must benoticed that considering the bodies alluded to as ships, they have different magnitudes, and consequentlydifferent degrees of stability, or power of carrying sail: the relation also which the resistance bears to thecapacity, or the relation which the resistance bears to the force or power of going forward, and themomentum will be different in each body. Taking the subject in this, which certainly is the proper pointof view, it of course becomes necessary to ascertain the relation which the resistance bears ro the capacity,and also the comparative degrees of stability possessed by the said bodies respectively, from whence suchconclusions may be drawn as are applicable to practice. As the said bodies ate all of the same formand dimensions in their midship section or body, differing only in the form and length of their fore andafter-bodies, the comparative stability will be nearly in proportion to the capacities of the different bodies-respectively; from whence it is conceived the comparative power, or quantity of sail, which they arecapable of sustaining, will be nearly in proportion to their different capacities. Acting on this datum,it appears, by mathematical calculation, that of the fig. A and t, plate 1, fig. A possesses die greatestadvantage, and fig. e the next in value. But supposing them actual vessels in motion at sea, then it maybe inferred that e would be materially the worst of the three; because its fore-body would not make somuch lateral resistance to keep the vessel up to windward, and would meet with more resistance in itspitching motion than either A or d.

“ It has been thought advisable/’ add these gentlemen very liberally, “ to say thus much respecting;the method-' of comparing the results of the experiments made on the said bodies, in order to prevent per-sons, who may not have it in their power to consider the subject fully, from drawing their conclusionscomparing their resistances only.”

Proceeding onwr-rd they remark, x ‘ That on comparing the resistance made bv the bodies * and /,their resistance will be found to be nearly the same ; but considering those bodies in the light of ships atsea, impelled forwards by the force of the wind acting on their sails, then, by mathematical calculation,it will appear that t has a very evident advantage ; its stability, or power of canying sail, being equal to17.523, while that of i is no more than 11.899. Thus does the long-bodv c possess not only the advan-tage of being ;*hlc to carry about one-third mere sail than », but has the additional power of overcomingsuch resistance as might he occasioned by the undulation of the water, or what is commonly called apoplEng sea, to its direct motion.”

It