446 Analijses of Books. [June, 



tide is falling generally, and the passage by Dungeness discharges- 

 the quantity brought by the ebb tide during that time. But 

 when the true ebb tide has run two hours and three quarters, it 

 is low water by the shore between the North Foreland and Fair- 

 leigh ; because the channel through the Straits of Dover (becom- 

 ing again too contracted to give vent to the great body of water 

 -which now presses from the Medway and the North Sea, aug- 

 mented by the currents and tides discharged from the great 

 continental rivers and inlets) now again accumulates in the 

 narrow passage, and in the Downs, from the North Foreland, 

 and thus begins, from the above stated period, to rise by the 

 shore. It thus continues to rise for the remaining two hours 

 and three quarters, at which time the regular ebb tide has ceased 

 to run to the westward, and it is low water every where without 

 the North Foreland, and to the westward of Fairleigh ; but 

 ■within these limits, it is half flood, in consequence of the accu- 

 mulation of the water during the latter part of the ebb tide. 



Such is Capt. Anderson's explanation of the tides at the straits 

 of Dover. The tide of the channel which flows east, continues, 

 along the French and Dutch coast till it is lost at the entrance 

 into the Cattegat. Another portion of it goes along the Kentish 

 coast, and gradually changing its direction, goes up the Queen's 

 channel ; while the tide along the east coast of Great Britain, 

 which flows south, gradually blends along with the English 

 channel tide at the Kentish Knock, which sand has probably 

 been accumulated by the meeting of the two tides, and proceeds 

 up the estuary of the Thames. 



Capt. Anderson shows that something very similar to the 

 tides at the straits of Dover, happens in the narrow channel 

 between the Isle of Wight and the English coast. 



V. 0)1 the Ova of the different Tribes of Opossum and Ornl- 

 ihorhi/nchus. By Sir Everard Home, Bart. — In the human 

 species, and in quadrupeds in general, the ova are formed in 

 corpora lutea, and pass into the uterus, to the sides of which 

 they become attached. When the fcetus is completely formed, 

 it is expelled by the vagina, and afterwards sucks the mother. 

 In the pullet, the yelk bags are formed in one ovarium, impreg- 

 nated in one oviduct, and hatched out of the body. Our author 

 has met with three tribes of animals which form the links 

 necessary to connect the common quadrupeds with birds as far 

 as generation is concerned. These are : 



1. 2'he Kangaroo. — In this animal the ova are formed in 

 coqjora lutea, as in the human species and common quadrupeds. 

 They receive their yelks in the fallopian tube, and their albumen 

 in the uterus. The ovum thus completed is impregnated in the 

 uterus, aerated by means of lateral tubes ; and when the young 

 has acquired the weight of about 12 grs. it is expelled from the 

 uterus, received into the marsupium, and attached to the nipplo 

 of the mother. " 



