TRANSACTIONS OF SECTION G. 837 
Section G.—MECHANICAL SCIENCE. 
PRESIDENT OF THE SEcTION—Sir W. H. Waits, K.C.B., Sc.D., LL.D., F.R.S. 
THURSDAY, SEPTEMBER 14. 
The President delivered the following Address :— 
In this Address it is proposed to review briefly the characteristic features of the 
progress made in steam navigation; to glance at the principal causes of advance 
in the speeds of steamships and in the lengths of the voyages on which such vessels 
can be successfully employed ; and to indicate how the experience and achieve- 
ment of the last sixty years bear upon the prospects of further advance. 
There is reason to hope that this choice of subject is not inappropriate. From 
the beginning of steam navigation the British Association in its corporate capacity, 
by the appointment of Special Committees, and by the action of individual members, 
has greatly assisted the scientific treatment of steamship design. Valuable con- 
tributions bearing on the resistance offered by water to the motion of ships, the 
conduct and analysis of the results of steamship trials, the efficiency of propellers, 
and cognate subjects have been published in the Reports of the Association. Many 
of these have largely influenced practice, and most of them may be claimed as the 
work of this Section. 
On this occasion no attempt will be made either to summarise or appraise the 
work that has been done. It must suffice to mention the names of three men to 
whom naval architects are deeply indebted, and whose labours are ended—Scott 
Russell, Rankine, and William Froude. Each of them did good work, but to 
Froude we owe the device and application of the method of model experiment 
with ships and propellers, by means of which the design of vessels of novel types 
and unprecedented speeds can now be undertaken with greater confidence than 
heretofore. 
As speeds incréase, each succeeding step in the ascending scale becomes more 
difficult, and the rate of increase in the power to be developed rapidly augments. 
Looking back on what has been achieved, it is impossible to overrate the courage 
and skill displayed by the pioneers of steam navigation, who had at first to face 
the unknown, and always to depend almost entirely on experience gained with 
actual ships, when they undertook the production of swifter vessels. Their suc- 
cessors of the present day have equal need to make a thorough study of the 
performances of steamships both in smooth water and at sea. In many ways they 
have to face greater difficulties than their predecessors, as ships increase in size 
and speed. On the other hand, they have the accumulated experience of sixty 
years to draw upon, the benefit of improved methods of trials of steamships, the 
advantage of scientific procedure in the record and analysis of such trials, and the 
assistance of model experiments. 
