ON MERCANTILE STEAM TRANSPORT ECONOMY. 113 
8 knots; and if the vessels be of a certain comparatively inferior type of 
build, as indicated by a lower coefficient, but still of such type as is commonly 
employed, the rate of freight per ton weight of cargo conveyed at the 12 knots’ 
speed on the passage referred to, was found to be about double the rate if 
conveyed at the speed of 10 knots per hour, and about three times the rate 
incurred by a speed of 8 knots an hour. 
Applying this estimated difference of cost incurred by difference of type 
to the aggregate trade of the country, as shown by the statistical returns of 
the Customs’ House, it was suggested that the pecuniary interest of the great 
paymaster “the public,” is involved to the extent of millions per annum, 
simply by the difference of type of build and condition of the ships and 
engines, and administrative management by which the foreign trade of the 
country, as respects transport, may be prosecuted. These points of my 
former paper are now referred to by way of introduction to the following 
paper, in which it is purposed to continue the subject-matter of my former 
dissertation, by showing the extent to which the weight-carrying capability 
of ships of given tonnage, whether rated by the gross register tonnage (new 
measure), under the Merchant Shipping Act of 1854, or by the tonnage 
builders’ measure O.M. (also commonly called “ burden,” and still generally 
in use, though legally superseded in 1835), is dependent on the relative pro- 
portions of length, breadth, and depth to which ships may be constructed ; 
and it is submitted for the consideration of the Association that this point of 
inquiry comes to be of special importance, seeing that the tendency of the 
present times to build vessels of great magnitude as respects length and 
breadth, whilst the load-draught is restricted by local circumstances within 
the definite limit of the minimum depth of water of the ports to be fre- 
quented, has a direct tendency to involve a condition of things as respects 
proportions of build adverse to public interests, for the public will have 
to bear the brunt of freight charges proportional to the cost expenses that 
may be incurred in the general administration of shipping affairs. We may 
just as well assert that the public have no interest in the efficiency of our 
army and navy, as that it has no interest in the efficiency of our commercial 
shipping. Rates of freight (excepting on occasions of national emergency ) 
must be ruled in the aggregate by the general average cost at which the 
general service of mercantile transport is actually performed, whether it be 
well or ill performed ; and the general introduction of proportions of build 
which can only perform their service at high rates of freight above the prime 
cost rates which would duly remunerate vessels of superior type, involves 
pecuniary considerations that may well form the subject of special statistical 
inquiry to be prosecuted at the instance of the British Association. The 
application of statistical science in connexion with shipping as a means of 
inquiry into the principles of Mercantile Steam Transport Economy, is, [may 
say, a new subject of inquiry, to which the British Association, and, I must 
add, the Society for the Promotion of Arts, Manufactures, and Commerce, 
have given public vitality. The question of Maritime Transport Economy 
has a bearing on public interests analogous to the operation of the rail and 
the telegraph. . 
A further object of this paper is, that by means of the following Table (A), 
which has been prepared to show the mutual relations which subsist in ships 
of given variations of build between Tonnage Builders’ Measurement O.M., 
Gross Register Tonnage, Weight Tonnage, or the capability of ships to carry 
weight of cargo, and the corresponding displacement when ships are loaded 
down to a determinate load line ; and Table B, showing the mutual relations 
of displacement, power, and speed, we may thus have the means of connect- 
I 
