940 Teaxsacttoxs of the American Ixstjtute. 



scale. Considerable difficulty has been heretofore found in obtaining 

 reliable measurements of high heat with the ordinary pyrometer, in 

 which the index finger is moved by two rods which expand at different 

 rates when exposed to the same degree of temperature. The rate of 

 ex^jansion of the same metal is not regular from the lowest to the 

 highest heat, and after being exposed to the higliest heat it does not 

 always return to its original size w'hen cold. It is hoped that the 

 plan of Bequerel will furnish wdiat has long been wanted, a reliable 

 instrument for measuring very high degrees of temperature. 



Dr. Yanderweyde here said there is a great want of a thermometer 

 that will measure high temperatures, say some 2,000 degrees. lie 

 found that an iron rod, when heated to a high temperature, will not 

 come back to its original place, and it has to be set every time it is 

 used. Bismuth and antimony, when used for tliis purpose, will melt 

 at some 600 degrees. But the use of platinum is very good, and 

 promises to become a reliable indicator of high heat. 



Silicon in Ikon. 

 Dr. Phipson, of London, announces that he has discovered that 

 silicon may exist in cast-iron, like carbon, either in a state of combina- 

 tion or in a state of diffusion merely in the form of graphite. Three 

 or four per cent of free silicon may exist in the iron without materially 

 preventing its conversion into good steel by the Bessemer process, but 

 a much smaller quantity of combined silicon will either render the 

 iron containing it incapable of being converted into steel, or will 

 cause the steel produced from such iron to be so hard and bad as to 

 be incapable of being w^orked. The position taken b}' Dr. Phipson, 

 if tenable, is one of great interest to commercial steel manufacturers. 

 He promises soon to publish a full account of his method of determin- 

 ing whether the silicon in a given specimen of iron is in a free or a 

 combined state. 



TuE Tklepiione. 

 Dr. Yanderwoyde exhibited a "telephone," invented by Mr. Kir- 

 path, of Troy, X. Y., by which musical sounds may be transmitted. 

 A cylindrical box, over one end of which a diaphragm of bladder was 

 stretched, was provided with a speaking tube. In the center of the 

 diaphragm was placed a small piece of platinum. This platinum was 

 in full connection with one pole of a galvanic battery, by means of a 

 wire attached thereto. The other pole of the battery connected with 



