TRANSACTIONS OF THE SECTIONS. 
107 
MECHANICAL SCIENCES APPLIED TO THE ARTS. 
On Impact and Collision, By Eaton Hodgkinson. 
Mr. Hodgkinson reported to the Section the results of certain ex¬ 
periments made by him on impact and collision, in continuation of 
those communicated to the Association in the year 1834 on the 
collision of imperfectly elastic bodies. The results were, 
First, That cast-iron beams being impinged upon by certain 
heavy masses or balls of metal of different kinds, were deflected 
through the same distance, whatever were the metals used, provided 
that the weights of the masses were equal. 
Secondly, That the impinging masses rebounded after the stroke 
through the same distances, whatever was the metal of which they 
were composed, provided that the weights were the same. 
Thirdly, That the effect of the masses of different metals imping¬ 
ing upon an iron beam were entirely independent of their elasticities, 
and were the same as they would give if the impinging masses were 
inelastic. 
Mr. Hodgkinson also gave the result of some interesting experi¬ 
ments on the fracture of wires under different states of tension, from 
which it appeared that the wire best resisted fracture and impact 
when it was under the tension of a weight which, being added to 
that impinging upon it, equalled one third of the force that was ne¬ 
cessary to break it. 
On the Solid of least Resistance. By J. S. Russell. 
Mr. Russell was called upon to give an account of a new form for 
the construction of ships, by which they should experience least re¬ 
sistance from the water in their passage through it. A vessel of 75 
feet keel and 6 feet beam had been built on this new formation, 
and made the subject of very accurate experiments, from which it 
appeared that this vessel, named the “Wave”, experienced much less 
resistance in passing through the water than vessels of the very finest 
formation and from the best builders on the old construction. 
Mr. Russell then detailed' very minutely the mode of forming any 
vessel on his plan when the length and breadth were given. The 
peculiarity, in general terms, appears to be the formation of the en¬ 
trance lines from parabolic arcs, so as to have a point of inflection at 
about one sixth part from the bow of the vessel, before which the bow 
is concave externally, giving the finest possible entrance at the stern, 
at an angle of contact infinitely small, and behind which the con¬ 
vexity is external and the formation elliptical to the midship section, 
after which the formation becomes wholly ellipsoidal. Mr. Russell 
had been induced to consider this solid as the solid of least resistance 
from a phenomenon that appeared to distinguish this form from all 
