584 ' TRANSACTIONS OF THE 



the metal, as is seen by using heavy hammers on large pieces of 

 cast iron. We therefore recommend a test of steam boilers by 

 steam of a pressure of at least twice the number of pounds per 

 square inch even to be used in practice, and at certain periods in 

 the use of the boiler, the first test to be repeated, thus the safe 

 use of boilers may be reduced to figures as in the case of cannon. 

 Any expense incurred by severe testing of steam boilers will be 

 saved a thousand times in avoiding the enormous loss of property 

 and life caused by their explosions. 



[The Journal of the Society of Arts and of the Institutions in Union, Nov. 1856.] 



This excellent society publishes weekly such papers as result 

 from about three hundred societies in union in England. They 

 send us their Journal gratis. — H. Meigs. 



EROWN LIME, 



Is found in several places in Wales. Constantly used by engi- 

 neers as a hydraulic cement. It is a very impure limestone, con- 

 taining much clay, to ivhich it owes its peculiar properties. All 

 limestone contains more or less clay (alumina), and it is this 

 skeleton of alumina which forms the rotten stone of commerce, 

 after all the calcareous matter has been removed. This removal 

 is effected by nature by means of some as yet unexplained chemi- 

 cal action, by which the hard, heavy limestone is converted into a 

 substance as light as cork ! resembling in color and appearance 

 the brown powder of a ripe puff ball. 



The rotten stone occurs in large masses on the outskirts of the 

 limestone band in the Brecon hills, and may be there seen in all 

 stages of transformation. One of the best places for seeing it, 

 with which I am acquainted, is about two miles from the Lamb 

 and Flag inn, near Ystradgynlais in the Swansea valley. It is 

 there collected in quantity for exportation to London, and the 

 principal dealer lives close to the Lamb and Flag. 

 STEEL MADE BY A NEW PROCESS IN THREE HOURS 

 FROM PIG IRON. 



A number of scientific gentlemen were called to witness the 

 operation, the discovery of Captain Uchatius, engineer in chief of 

 the Imperial Arsenal at Vienna. It was done at the Albion 

 engine works of Messrs. Rennie & Sons, in Llolland street, Elack- 

 friars road, in the presence of numerous spectators, on Saturday 

 last the 11th of October, 1856. The mode of operation was read 

 by Mr. Charles Lenz, the partner of Capt. Uchatius. He stated 

 the usual methods of England and > probably of all the world in 

 making steel, that is to convert say Swedish or Russian bar iron, 



