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84. Report to the Directors of the Great Western Railway Company on the Broad Gauge, &c. (August 1838) 525   He is desirous of combining his views into one report (p. 525)—The difficulties have been overcome, or are gradually diminishing (p. 525)—And the result justifies the attempt which has been made (p. 526)—The gradients of the Great Western Railway are favourable (p. 526)—Advantages of the broad gauge (p. 527)—Reasons for adopting it (p. 528)—Additional cost in construction is very slight (p. 529)—Weight of carriages (p. 530)—Freedom from accidents (p. 531)—Greater space for works of locomotives (p. 532)—The greater width gives scope for improvement in every part (p. 532)—Speed obtained (p. 532)—Design of the engines (p. 533)—The continuous system of permanent way is best adapted to high speeds (p. 535)—Calculations as to its cost compared with that of a well constructed line with stone blocks (p. 537). 85. Report to the Directors of the Great Western Steam-Ship Company, recommending the Adoption of the Screw Propeller in the ‘Great Britain’ Steam-ship (October 1840) 539   This subject will be considered under two heads: 1. The efficiency of the screw propeller, compared with the paddlewheel. 2. The advantages or disadvantages attending its use (p. 539)—The first question involves the consideration not merely of the effect produced, but also of the proportionate power absorbed in producing that effect (p. 539)—Observations on the slip of the paddlewheel and screw in the ‘Great Western’ and ‘Archimedes,’ respectively (p. 540)—The result of the comparison being, that with similar areas the screw will meet with at least equal, if not a greater resistance, and will consequently slip as little as or less than the ordinary paddle-board (p. 542)—Refutation of the common error, that the action of the screw is a very oblique one, and that it imparts a considerable rotatory motion to the water (p. 543)—Description of the action of the screw (p. 543)—The result of the experiments is that, as compared with the ordinary paddlewheel of sea-going steamers, the screw is, both as regards the effect produced and the proportionate power required to obtain that effect, an efficient propeller (p. 548)—Objections to the use of the screw propeller (p. 548)—Answered seriatim (p. 549)—Statement of the principal advantages peculiar to the use of the screw (p. 552)—The result of these enquiries is a strong and decided opinion in favour of the screw propeller being adopted in the ‘Great Britain’ steam-ship (p. 557).