84 REPORT—1857. 
Lord J. Hay and a body of shipowners, who reported that “ the equi- 
table basis on which charges for dock, light, harbour, and other dues, 
is that of the entire cubic contents of a vessel measured externally.” A bill, 
based on this recommendation, was brought in, computing the tonnage by 
means of diagrams of section, and curves of areas, with a scale of dis- 
placement. 
This bill was opposed by the owners of timber ships and the builders of 
iron vessels, and from this and political causes was deferred. 
At that time I proposed that the principle of the bill of 1850, and of the 
plan recommended by Mr. Moorsom for internal measurement, should be 
embodied in one bill, and the mean of the two measurements be taken as 
the basis for register tonnage; and before the bill was actually passed, I 
submitted that this could still be accomplished by combining the Rule No. 1 
of the bill of 1850 as well as Rule No. 2, which already forms part of the 
bill, by an alteration of the clauses 20, 21, 22, of the present act. 
Register tonnage is necessary for statistical purposes, but should approxi- 
mate the old builder’s tonnage, in which the statistics of shipping have, 
from the earliest times, been kept, and which more nearly assimilates that 
of other nations. There are, however, objects to be attained by a more 
comprehensive system of tonnage registration, viz. the safety and efficiency 
of the ships, their mercantile capabilities, and to supply scientific data 
for facilitating a comparison of the various types of ships, including a record 
of their burthen in weight or displacement, capacity, strength of material and 
steam-power. The practicability of obtaining this record is exemplified by 
the annexed table of the dimensions and proportions of ships and engines 
and comparative analysis of their capacity, resistance, and the result of test- 
trials and performance at sea; the particulars recorded of many affording 
data for estimating the comparative dynamic merits of ships by the co-effi- 
cient of their displacement or index number. The additional measurement 
and data required are shown in the table. (Appendix A.) 
With this view it is proposed to substitute for the forms now sent to the 
Custom-house, the record, on the present builder’s “ certificate, of all parti- 
culars of dimensions, old tonnage and measurement by new rule, mentioned 
in the accompanying form, giving the builder's construction, load, draft, 
displacement, and area of midship section, as well as the launching draught, 
and estimated weight of hull and fittings as the light water-line, from which 
a scale of displacement and area of midship section may be formed at any 
draught of water.” (Vide Appendix B.) 
These particulars relating to the external bulk and internal space, with 
the draught, displacement, and area, would not only give the internal capa- 
city, but also the capability for carrying weight of cargo, as well as the data 
forming a scale for displacement and area of midship section at any draught 
of water, whence may be deduced the relative efficiency of different vessels. 
I consider the present plan of taking and recording the internal measure- 
ment, and the mode of computation to be practically inefficient for obtaining 
a correct mensuration of vessels, and that the formula and mode of calcu- 
lating are extremely liable to error, without the means of testing their cor- 
rectness, as was suggested by the Tonnage Committee of 1849. 
- The Act of 1854, though nominally adopting the same scientific rule, in 
effect abandoned the most important part, viz. the use of the diagram and 
curves of areas. 
By using paper ruled to a scale in the formation of the diagram, the com- 
putation is rendered both easy and correct, and a record of these measure- 
ments, &c. in the certificate of the surveyor would furnish the owner or 
