416 
MR. E. J. REED ON THE UNEQUAL DISTRIBUTION OF 
approximation to the maximum bending-moment, taking account in each case of the 
action of the forces on one side only of the station considered. He also attempts, but 
with less success, to find expressions for the deflections corresponding to the bending- 
moments, in order to estimate the amount of hogging. Next he shows that the longi- 
tudinal fluid pressure has a considerable bending-effect on a ship afloat, following, no 
doubt unconsciously, in the path of Euler, but not falling into the error which Euler 
had made in supposing that this pressure tended to reduce the hogging caused by the 
vertical forces. The great merit of Dr. Young’s paper consists in the fact that, 
throughout the investigations of the strains of ships, quantitative results based upon an 
actual ship are given. No preceding writer, to whom I have referred, followed this 
course, although Bouguer and Don Juan took hypothetical cases to illustrate their 
methods. Dr. Young also takes a much more complete review of the principal causes 
of straining than any of his predecessors. In dealing with the question of the strength 
of ships, however, he is not so successful. 
About two years after the publication of Dr. Young’s paper in the Philosophical 
Transactions, appeared another written by the eminent French geometrician Dupin. It 
was professedly “ A Theoretical Examination of the Structure of English Vessels,” 
meaning thereby vessels built on the diagonal system. Although Dupin followed 
Dr. Young and Seppings in the discussion of this subject, he contributed several addi- 
tional features possessing both interest and importance. 
Without further preface I shall pass, first, to the consideration of the actual distri- 
bution of weight and buoyancy in various classes of ships when floating in still water. 
The testimony of Bouguer, Euler, and Don Juan puts it almost beyond doubt that in 
the older types of wood sailing-ships there was generally a great excess of buoyancy in 
the middle, and deficiencies of buoyancy at the ends only. In later sailing-ships, such 
as that referred to by Dr. Young, there were portions of the amidship length (in wake 
of water, ballast, and other concentrated weights) of which the weight exceeded the 
buoyancy ; and this excess, as well as that due to the heavy extremities, was counter- 
balanced by the surplus buoyancy of the portions of the ship intermediate between the 
middle and the extremities. With the introduction of steam as a propelling agent, and 
of very largely increased lengths and proportions for ships, a vastly different state of 
things has been brought about in the distribution of weight and buoyancy. At the ends 
of ships there still remains an excess of weight, exaggerated in many cases by the adop- 
tion of very fine under-water lines in combination with heavy bows and stems above 
water ; but the distribution of weights in the fuller parts of the ship becomes much 
changed. How great the change has been we may infer from the fact that at present 
merchant steam-ships are in actual employment of which the length is 400 feet, and the 
proportion of length to breadth exceeds 10 to 1, both length and proportion having been 
more than doubled since the introduction of iron into ship-construction and steam into 
ship-propulsion. Ships of even greater length, both actually and proportionately, to 
breadth are being constructed for trading between Europe and the East through the 
