332 



SCIENCE. 



[N. S. Vol. I. No. 12. 



ence in mouuting stone skeletons realize 

 what an extremely difficult undertaking it 

 is, and will judge of this pai'ticular mount 

 with leniency ; at the same time, an exam- 

 ination of the figure, or still more of the orig- 

 inal specimen in the Museum, shows that 

 the limbs have been placed in an unneces- 

 sarily awkward and impossible position. 

 Thei'e was no necessity for placing the hind 

 limbs so far in front of the center of grav- 

 ity of the posterior half of the bodj^, or for 

 turning the fore feet so far inward that lo- 

 comotion in a forward direction would be 

 rendered impossible. 



The latest Bulletin from the Museum of 

 Comparative Zoology is Professor Agassiz's 

 ' jReconnoissanee of the Bahamas and of the 

 elevated coral reef of Cuba in the steam yacht 

 Wild Duch, January to April, 1893,'' covering 

 200 pages, 47 plates, and a large number of 

 illustrations in the text. It contains a com- 

 plete survey of this remarkable coralline 

 region, and is not only full of original ob- 

 servations and notes of great value, but 

 brings the region far more easily within the 

 reach of future biological and geological 

 exploration. As the survey in the Wild 

 Duck continued over only four months, it 

 has rather the reconnoissance character of 

 that made by Professor Agassiz in the ' Al- 

 batross,' on the west coast of South America, 

 than the thoroughness of the author's work 

 upon the Blake. The Wild Duck was placed 

 at Mr. Agassiz's disposal by Mr. John M. 

 Forbes, and while not fitted like the Govern- 

 ment vessels for deep sea work, proved to 

 be admirably adapted for cruising on the 

 Bahama banks, her light draft enabling her 

 to go to every point of interest and to cross 

 and recross the banks where a larger vessel 

 could not follow. The gi-eater part of the 

 Bulletin is descriptive. A number of im- 

 portant problems are discussed, the author 

 closing with an expression of his own views 

 upon the formation of coral reefs, as con- 



firmed by this exploration of the Bahamas : 

 " Substitute subsidence for rising land and 

 remembering that reef coral will not grow 

 at a greater depth than twentj' fathoms, we 

 eliminate subsidence as a factor unless we 

 are prepared to accept or imagine a sjti- 

 chronism between the growth of corals and 

 subsidence in a great number of the districts 

 in which they flourish, of which we have no 

 proof." 



WELDING OF IRON. 



At the last meeting of the Eoyal Society, 

 according to the London Times, a paper on 

 Iron and Steel at Welding Temperatures \yy Mr. 

 T. Wrightson, M. P., was read. The ob- 

 ject of the paper was to demonstrate that 

 the phenomenon of welding in iron is 

 identical with that of regelation in ice. 

 The author recapitulated some experiments 

 which were made by him in 1879-80 upon 

 cast iron, and proved the fact that this 

 form of iron possesses the property of ex- 

 panding while passing from the liquid to 

 the plastic state during a small range of 

 temperature, and then contracts to the 

 solid state, and that the expansion amounts 

 to about 6 per cent, in volume. This prop- 

 erty of iron resembles the similar property 

 of water in freezing, which, within a range 

 of about 4° C, expands about 9 per cent, 

 of its liquid volume, and then contracts as 

 the cooling proceeds. Subsequent investi- 

 gations at the Mint appeared to prove that 

 wrought iron at a welding temperature pos- 

 sesses the same property of cooling under 

 pressure which was proved bj^ Lord Kelvin 

 to exist in freezing water, and on wliich 

 demonsti'ation the generally received theory 

 of regelation dei^ends. The author distin- 

 guished the process of melting together of 

 metals from that of welding. Either pro- 

 cess forms a junction, but the latter takes 

 place at a temperature considerably below 

 the melting point. The well-known and 

 useful property of weldiag in iron appeared, 



