AV'are on J'aults and Bridges, 297 



I'he average time of high water London Bridge spring tides 

 is nine minutes earlier below than above bridge ; of neap tides, 

 fifteen minutes. 



Tile tide rises 15 feet out 

 of 18 teet 6 inches in half 

 the time ol' the flood. 



The stream at spring- 

 tides runs upwards about 20 



c 



Ft. In. H. .\i. 



18 6 high water at 4 4-4 



18 I flood 3 33 „ „^ 



15 i flood '2 22"^ minutes after it is high wa- 



b Q \ flood 111 ter by the shore, and in the 



low water mark middle from 30 to 32 mi- 

 nutes. 2d Rep. Lond. Port. 

 LApp.C. 3. 



The last in this interesting collection is a Tract on the Prin- 

 ciples of Pendent Bridges, with references to the properties of 

 the Catenary, applied to the Meiiai Bridge ; and contains a 

 Theoretical Investigation of the Catenary. 



The work is illustrated with 20 very useful plates. 



Journal of the Academy of Natural Sciences of Philadelphia. 



The difficulty and tardiness with which the transactions of 

 foreign Societies make their way to this country, and the 

 comparative ignorance in which we consequently remain re- 

 specting the discoveries of the more active continental labourers 

 in the field of zoology, is a subject of much regret and em- 

 barrassment to the British naturalist. There are several societies 

 in Berlin, Vienna, and other European and trans-atlantic capi- 

 tals, expressly formed for the cultivation of tliis science, and 

 supported by the contributions of eminent men, active and 

 zealous in the investigation of its various branches; but their 

 writings ccnne to us by chance, anil sometimes after a lapse of 

 years. An unaccountable negligence on this point pervades 



aroheH each \'.Vl feet ^pilll ; and .500 t'ect in length of that bridge might have 

 been saved ; and in tliat case, the whole of the inclined roads on the Surry 

 side, parallel with the river, and the greater pai't of the compensation ex- 

 pense would have been saved also : for the descent would have terminated 

 jOO feet nearei- the river. The middle arch would then have been in the 

 middle stream at low water nearly. A much greater saving even than this 

 might have been made by following the example set at \'erona. The ex- 

 cessive magnificence and strength of tliis l>ridge surely manifests the opu- 

 lence of its founders as mui'h us the great (ivramid of Kgyjit docs tliat of 

 ( 'hcops. 



'I'he cubical dimensions of the stone sunk to make the Breakwater nt 

 Plymouth, and of the stone, brick, ami tunher used at Sheerness, may bear 

 a comparison with tho^c of this pyramid, if we are i|s ostentatious of our 

 wealth as the ICgyptian. we :u>ply it to work^ intended for the pul)lic benefit. 



$) Vpp. n. :{. Uep. \.tM(\. Port. 



Ij Month. Ma.;. March, iHlfi, .ind Mom. ( 'hron. -'(Jih May, 181J. 

 Vol. ^Jl. No. 300. .'//^r/V 1S23. Pp all 



