Its functions may be classified roughly under the heads of collecting information, registration, inspection, and authorising acts or undertakings of a public nature; although any such classification is sadly confused by the fact that duties of more than one kind have been conferred upon the board in regard to the same subject-matter, and even by the same statute. To the first of these classes belong its functions in collecting and publishing statistics relating to domestic and foreign trade, and giving advice on commercial matters to other departments of the government. To that class belong also its functions as a labour bureau in preparing statistics about labour, wages and other matters touching the interests of workingmen. In this connection it has power also to act as a board of conciliation in labour disputes, and to name arbitrators or conciliators. Under the head of registration may be mentioned its duties in maintaining the standards of weights and measures; registering joint-stock companies; examining and recording patents and trade-marks; and keeping a register of ships and seamen. Under the head of inspection come its functions in ascertaining that merchant vessels are in a seaworthy condition, and properly laden, officered, manned and equipped; with the power to detain unseaworthy craft. Under the same head may be classed its control over harbours, its duty to see to the enforcement of the laws relating to railways[109:1] and to inquire into the causes of railway accidents and disasters at sea. As an example of the final class of powers may be cited the fact that the by-laws of a railway company require for their validity the approval of the board; but a far more important instance is to be found in its control over the building of new lines of railway, over new undertakings for the supply of water, gas and electric light, and over the construction of tramways and light railways, the last being a recent invention legally very different, but physically indistinguishable, from tramways. This control is exercised by means of provisional orders, prepared by the board after an investigation and a hearing of all the persons interested, and then confirmed by Parliament.[109:2] The petitioner is not, indeed, compelled to resort to a provisional order, but may avoid the direct control of the Board of Trade by means of a private bill in Parliament. But a provisional order is far less expensive; and even when the procedure is by private bill the board endeavours to exert its influence by scrutinising the bill, and bringing to the notice of the officers of the House any departures from the general policy of legislation.[109:3] The result is that the board has an effective, although by no means an absolute, control over these matters.