266 REPORT — 1861. 



tion of double-flanged girders is not affected by the mode of construction adopted 

 in the web ; in other words, if two girders of equal length and depth, one a lattice, 

 the other a plate girder, have the same strains per sectional unit transmitted thi-ough 

 their flanges, they will both deflect to the same extent. Also, when a girder is of 

 uniform strength, that is, when aU parts are equally proportioned to the transmitted 

 strain, the deflection-curve v.nl\ be a cii-cle, and the central deflection may be simply 

 expressed by the following equation — 



where D = the central deflection. 



/ = the length of the gii'der. 

 d = the depth. 

 X = the difference in length of the flanges after deflection. 



On Bailey's Steam-pressicre Oauge. By W. Tate. 



On Pro;perty in Invention ami its Effects on the Arts and Manufactures. 

 By T. Webstee, F.B.S. 

 The author pointed out that considerations of public policy had led to certain rules 

 or laws respecting the use and enjoyment of all property, and that the same principles 

 to which the origin of aU property is to be referred had peculiar claims to recogni- 

 tion with regard to the inventor. To say that an inventor may retain command 

 over his invention by secrecy is to propose an impossibility in a majority of cases, 

 and in a few cases in which it might be done the ettect would be to convei-t his art 

 into a mystery and to introduce practices long since condemned. _ The author pointed 

 out the fallacy of stigmatizing patents as contrary to the principle of free ti-ade, as 

 was commonly done. He admitted the injury done by the iudiscriminate gi-ant of 

 patents ; and this, which might be remedied, ought not to be used as an argument 

 against the system. He pointed out that although for small inventioJls and such 

 as could be quickly introduced a patent might not be needed, yet that where time 

 and capital were required to introduce the inventions into use, such inventions would 

 not be made and perfected useless the inventors were protected fi'om piracy by 

 letters patent. He thought the cases of obstmction, in practice, were more imagi- 

 nary than real. The law admitted of successive patents for improvements, and 

 practically it was rare that a prior inventor would not come to reasonable terms 

 with a subsequent one. At all events, the case might be met by applying to this 

 species of property that which the legislature had already applied to other Muds of 

 property, viz., the powers of the Lands Clauses Consolidation Act, where lands 

 were taken compidsorily, and compel patentees to grant licenses upon equitable 

 terms. 



APPENDIX. 



On the Causes of the Phenomena of Cyclones. By Isaac Ashe, A.B., M.B. 



The author criticised ]\ir. Redfield's view of the formation of cyclones, as given 

 in Smiman's Journal, vol. xxxiii. p. 56, namely, that they are formed by the meet- 

 ing in the upper regions of the atmosphere of two cmi-ents, a hot and a cold, which, 

 infolding each other, generate a horizontal rotation in a body of air, and that, one 

 extremity of this rotating body of air descending to the earth, the horizontal rota- 

 tion is changed to a vertical one. Such a view would not account for the fact that 

 the rotation is invariably from left to right in the southern hemisphere, and from 

 right to left in the northern, as the direction of the vertical rotation would be altered 

 according as it would be one or the other extremity of the vertically rotatingbody 

 of air that chanced to descend to the earth. Mr. Ashe considered that the inva- 

 riably observed phenomenon pointed to a cause admitting of no variation, and sug- 

 gested that, in consequence of the dim-nal rotation of the earth being slower as we 

 go polewards, a volume of air, rushing towards a centre of rarefaction near the 



