344 



proportion to the strength which it will ultimately attain, and it may 

 be ill adapted to the purposes of labour. 



Mr. Knight remarks, that with respect to sex also, the influence of 

 the female entirely predominates, as particular females will produce 

 all their offspring of one sex, either male or female ; but by attending 

 to the numerous offspring of a single bull, ram, or horse, he has never 

 witnessed any considerable difference in the numbers of the two sexes. 



The size and form of the eggs of oviparous animals being depen- 

 dent wholly on the female, regulate of course the size of the off- 

 spring, and in this respect resemble the seeds of plants ; but their 

 formation, nevertheless, appears to depend on different laws; for the 

 eggs of birds, fishes, and insects, attain their full size in total inde- 

 pendence of the male ; but in seeds, on the contrary, the whole in- 

 ternal organizati6n depends on the influence of the male. For though 

 a gourd may produce fruit, apparently perfect, without impregnation, 

 and although even the seed-coats acquire their natural size and form, 

 these coats are perfectly empty, without the slightest vestige of co- 

 tyledons or plumula, or anything that appears to correspond with the 

 internal organization of a complete seed. 



On the Effect of westerly Winds in raising the Level of the British 

 Channel. In a Letter to the Right Hon. Sir Joseph Banks, Bart. 

 K.B. P.R.S. By James Rennell, Esq. F.R.S. Read June 22, 1809. 

 [Phil. Trans. 1809, p. 400.] 



The recent loss of the Britannia East Indiaman having appeared 

 to the author intimately connected with those observations which he 

 formerly communicated to the Society concerning a current that oc- 

 casionally prevails to the westward of Scilly, he has thought the cir- 

 cumstances deserving of particular inquiry, as it may be of use to re- 

 cord them as a warning against dangers which may probably be 

 avoided. 



During the prevalence of westerly winds, it is well known that 

 they occasion the height of the tides to be greater in the southern 

 parts of Great Britain, even as much as ten feet, in violent storms 

 from that quarter ; and it has also been remarked, that the flood-tide 

 runs an hour or more longer than at common times ; or, in other 

 words, that a current overcomes the ebb-tide. And since the direc- 

 tion of this current must be influenced by the form of the adjacent 

 shores, it is evident that the shore in the neighbourhood of Boulogne, 

 which tends very directly northward, will cause a northerly current 

 through the Straits of Dover. 



It appears to have been under these circumstances, that the Bri- 

 tannia was lost. Having been driven up the Straits by a violent gale 

 from the south-west in thick weather, which prevented a view of the 

 lights, the pilot was left entirely to the reckoning and the lead : but 

 as he was not aware of the unusual current that prevailed, he was 

 driven unexpectedly on the back, or eastern side of the Goodwin 

 Sands. 



