928 APPENDIX. 



These kilns have been worked with great success in India and are now 

 being introduced into this country. 



They are the cheapest kilns with regard to cost of building and effect a 

 saving of nearly two-thirds of the expenditure usually involved. 



These kilns are especially suitable for temporary works. 



The effective mode of feeding invented by Hofmann, has also been applied 

 by Bull to his kiln with great success. 



996b. Model of Hofmann's Circular Kiln. 



Hermann Wedekind. 



Hofmann's Patent Annular Ovens for the continuous burning of bricks and 

 tiles, limes and cements, at a saving of from two-thirds to three-fourths of the 

 fuel usually employed. 



It is the joint invention of M. Fred. Hofmaun, of Berlin, and M. A. Licht, 

 of Dantzig. 



It is now well known and appreciated by the trade in this country, and has 

 been extensively employed by the Government on the extensive works at 

 Portsmouth Dockyard, where five of the kilns have been working at a great 

 saving to the country. About 1^ millions of bricks are daily burnt in them 

 in England alone. Taking coal at an average price of 10s. per ton, this in- 

 vention will give a saving of at least 60,000/. per annum. In burning lime 

 equally favourable results have been realised as in burning bricks. 



1249e. Antiuori's First Apparatus for Induction 

 Sparks. Prof. Dr. Dove, Berlin. 



This apparatus was bought at an auction in Florence, after Nobiii's 

 decease. 



1286b. Thermo-Eleetric Apparatus by Seebeck. 



1. Ring of copper and antimony. 



2. Cylinder of copper and antimony, 46 mm. in diameter and 



22 cm. long. 



3. Six circular discs ; diameter 10 cm. ; of copper, brass, and 



other alloys. 



4. A square disc, 16 cm. 

 o. Two rods, Bi. Sb. 



Prof. Dr. Dove, Berlin. 



(Property of the Eoyal Academy of Sciences at Berlin.) 



1336. Dynamo-Electric Light Apparatus, making 480 

 revolutions per minute, with an expenditure of 6 horse-power gives 

 a light of from 12,000 to 15,000 normal candles. 



Siemens and Halske, Berlin. 



In these machines the inner iron core is fixed. Around this core revolves 

 a German silver bobbin, upon which is wound in a peculiar manner eight 

 double circuits of covered copper wire, these circuits terminating in the 

 metallic segments, which are successively brought as two opposite poles into 

 contact with the wire brushes. The magnetic field in which this bobbin 

 revolves (on its own axis) is formed by electro-magnets, the continuation of 

 the cores of which are curved iron bars, and these bars are so arranged as to 

 be brought as near as possible to the revolving bobbin. The current given 

 by these machines is continuous and in one direction. 



