SCIENTIFIC SUMMARY. 
325 
also, as is supposed, the Crinoids received their nourishment and the water 
necessary for respiration through the arms and the covered channels con- 
nected with them by an internal mouth, probably the power of expansion 
and contraction above alluded to may have been used by the Crinoids for 
the purpose of rapidly ejecting water to clear the internal passages, as is 
done by the Ascidium or sea-squirt, and by the mollusca generally. No 
doubt many objections may be raised to this supposed approach of two dif- 
ferent and perhaps distinct orders ; we know, however, that nature draws no 
hard lines, but abounds in connecting links, and it may be possible that the 
Molluscoidea and the Echinodermata are connected by the link now sug- 
gested. 
MECHANICAL SCIENCE. 
Strains in Ships. — Mr. E. T. Reed, C.B., has communicated to the Royal 
Society a paper containing the results of the remarkable and elaborate 
investigations of the strains in ships of various types, in which he was 
engaged before leaving the office of Chief Constructor. The enormous 
labour involved in such calculations has hitherto prevented the attainment 
of definite and precise results, even for still-water strains. Mr. Reed has 
carried out the necessary calculations for several types of vessel, and more- 
over has estimated the straining action due to the position of a ship on a 
wave-crest and in a wave-hollow. The importance of these calculations, as 
affecting the choice of one type of vessel rather than another, may be 
judged from the following comparison of the straining action in the 
Minotaur and Bellerophon : — 
On Wave-Crest. 
“ Minotaur.” 
Maximum shearing strain . . . 1,365 tons. 
Maximum bending movement 140,300 foot tons. 
“ Bellerophon.” 
555 tons. 
43,600 foot tons. 
In Wave-Hollow. 
Maximum shearing strain . . . 695 tons. 640 tons. 
Maximum bending movement 78,800 foot tons. 48,800 foot tons. 
It may be useful to note that a brief abstract of this paper appeared in the 
“ Mechanics’ Magazine ” for May 5. 
The u Devastation ” and the u Cyclops.” — The Committee on Designs for 
Ships of War have made a report to the Admiralty respecting these vessels. 
The result at which they have arrived is, that “ ships of the Devastation 
class have stability amply sufficient to make them safe against the rolling 
or heaving action of the waves and in addition, u as the steadying effects of 
bilge keels and of friction have been neglected in their calculations, the 
errors are on the safe side.” They estimate that the wind might produce an 
angle of heel of five degrees in addition to that due to the roll of the 
waves, and that with this the ship would still have an ample margin of 
stability. They recommend that the Devastation should be completed with 
YOL. X. — NO. XL. Z 
