Now it is inseparable from the nature of all great changes of system that particular interests must, occasionally, suffer from causes which contribute to the general good; it is, therefore, possible in this instance, that particular trades may have been injuriously affected, while the general interests of British shipping have been promoted. The statistical accounts of British tonnage employed at any given time afford a very imperfect test of the actual condition of the shipping interest, the more so as shipping is often employed with very inadequate remuneration; but this remark does not apply to periods of time extending over several years; hence, the shipping returns of the nine years since the repeal of the Navigation Laws may be fairly held to supply sufficient evidence of the influence that measure has exercised on the permanent interests of British shipping. [Sidenote: Board of Trade report and returns.] Consequently a table was prepared by the Board of Trade to show the total aggregate tonnage of British and foreign vessels, respectively, entered and cleared, with cargoes and in ballast, at ports of the United Kingdom in each year from 1842 to 1857 inclusive, a period comprehending eight years before and eight years after the repeal of the Navigation Laws.[187] [Sidenote: English and foreign tonnage.] It will be seen from this table that during the first period British tonnage advanced from 6,699,995 tons in 1842 to 9,669,638 in 1849, being an increase of 2,969,643 tons. In the second period it advanced from 9,442,544 tons in 1850 to 13,694,107 tons in 1857, being an increase of 4,251,563 tons. In the same period the progress in the employment of foreign tonnage in the trade of the United Kingdom has been from 1842, 2,457,479 tons; to 1849, 4,334,750 tons; increase 1,877,271 tons. From 1850, 5,062,520 tons; to 1857, 9,484,685 tons; increase 4,422,165 tons. It must be borne in mind, that these tables only show the state of the trades before the repeal was completely carried out for British and, partially so, to foreign ships, and that, in order to estimate the full effect of the measure on British shipping, it is necessary, also, to show the number of British ships built and registered during the respective periods.[188] There are two features in these returns deserving special notice. 1st. According to the opinion of the Board of Trade this account shows a larger relative increase than that of the previous returns relating to the employment of tonnage, while it, at the same time, confirms the hypothesis that many British ships now find an employment in the indirect trade of foreign countries, which, of course, does not appear in the accounts rendered in England. Indeed, during the period of protection, there was an actual decrease in the amount of tonnage built and registered, while a large increase took place in the second period of open competition. [Sidenote: Sailing vessels and steamers in home and foreign trades.]