[15] Ville de Paris, length 185.62 feet; breadth 52.7 feet; Commerce de Marseilles, length 208.33 feet, breadth 54.79 feet. [16] Old Bellerophon, length 168 feet, breadth 47.33 feet; New Bellerophon, length 192 feet, breadth 49 feet. [17] Vide this gentleman’s speech on the Shipping Interests in the House of Commons, May 1827. [18] Called by Capt. Brenton the Ohio; but it appears from Lieut. De Roos’ personal narrative, just published, that the Ohio is a two-decker of 102 guns. It is to be supposed, therefore, that the three-decker of 135 guns, called the Pennsylvania by the latter, is the ship alluded to by the former. It is a matter of great regret that Lieut. de Roos has not presented us with the precise dimensions of these ships. [19] These dimensions carry the ratio of the length to breadth above 4-1/3 to 1. [20] The French Admiral Willaumez, in his “Dictionnaire de Marine,” published in 1820, says under the article _Frégate_, that as far back as 1804, he had proposed a plan for a frigate of the largest size, with a round stern, wherein the quarter galleries were suppressed: the first frigate upon his plan was built at Brest about 1821. [21] As the square root, so that to get _twice_ the velocity, _four_ times as much canvas must be spread; and this is the most favourable estimate that can be made. [22] Vide Mr. Huskisson’s speech on the Shipping Interests. [p039] _On Malaria_. No. II. [Communicated by J. Mac Culloch, M. D., F. R. S., &c. &c.] Having pointed out, in the former paper on this subject, the nature of the soils or places, of whatever description, by which malaria is generated, it remains to notice a few other circumstances connected with its natural history, a knowledge of which is essential for the purposes of prevention; and finally to describe such modes of prevention, applicable to these several circumstances, as have been found useful in guarding against the attack of diseases from this cause. Under the first head, there remain to be considered, the effects of climate and season; the changes which occur in the production and propagation of malaria, from various natural and artificial causes; and also, the various modes in which it is propagated.