Intelligence and Miscellaneous Articles. 231 



a favourable exposure. No other locality showing this deposit has 

 yet been found in the county. 



Two plotted diagrams are given to show the developments of the 

 beds in the different sections, and to illustrate the result of the 

 Bajocian denudation. Iu an Appendix to Parts I. and II. various 

 notes are given, and attention is called to a remarkable oyster as 

 a document of historic value evidencing the Bajocian denudation. 



Part III. of the paper gives the chronological sequence of brachio- 

 poda in Dorset and the Cotteswolds in the Inferior Oolite, to show 

 their value for purposes of exact correlation when ammonites are 

 absent ; and to illustrate that the brachiopods are a good medium of 

 exchange in regard to the strata of the Cotteswold and Dorset 

 districts respectively, that in some cases they are such in regard to 

 the two districts, and in other cases they fail in this respect, so 

 that ammonites become the only true medium of exchange between 

 the beds of different basins. 



An Appendix to Part III. describes certain new species of 

 brachiopoda, and gives notes upon others. 



XVIII. Intelligence and Miscellaneous Articles. 



ON THE MAGNETISM OF ASBESTOS. BY L. BLEEKRODE. 



IN the 'Electrical Be view' Mr. A. S. C. Swinton* states that 

 -*- asbestos is rather strongly magnetic. As this fact must be 

 taken into account in constructing certain measuring instruments, 

 I have repeated the experiments in question, and have found that 

 in the material at my disposal t the magnetic force is even more 

 strongly developed than Svvinton mentions, in so far that powerful 

 electromagnets were not necessary, but an ordinary good steel 

 magnet was sufficient for demonstrating it. It is surprising that 

 this property, which asbestos possesses in a higher degree than 

 most magnetic substances (with the exception of nickel and cobalt), 

 should have been so long overlooked, notwithstanding that this 

 material has been so much in use, especially in late years. 



Earaday, in his well-known investigations on the magnetic 

 behaviour of various substances, places asbestos among the feebly 

 magnetic bodies, which is remarkable, as he was working with a 

 very strong electromagnet. Long before that, in the year 1778, 

 my countryman BrugmansJ, who discovered the diamagnetism of 

 bismuth, in his researches on the magnetism of various bodies 

 mentions asbestos as a tolerably strong magnetic mineral. He 

 states that the steel magnet which was used in the experiments 



* Electrical Review, vol. xxxiv. Oct. 5, 1891. 

 f From Bell's Asbestos Company. 



X l Magnetismus seu de affinitatis ruagneticis observationes,' trans- 

 lated into German by G. Eschonbach : Leipzig, 1781, p. 138. 





