for the year 1880. xxiii 



the dynamic methods of Siemens, Gramme, and others, as in 

 the electric light, can now be used for the transmission of 

 power to a distance, so that a current generated by such a 

 machine, at the Exhibition, for instance, could be conducted, 

 say, to the wharfs by suitable wires, and there made to 

 operate on cranes, pumps, and other machines with com- 

 parativety small loss of original work. As an example of 

 power transmitted in this way, Dr. Werner Siemens has 

 actually driven a carriage along a short railway by an 

 electric machine at one end of the line, using the rails as 

 conductors for conveying the current to the carriage as it 

 travels away. " At a recent meeting of the Society of Tele- 

 graph Engineers in London, also, Mr. Siemens exhibited an 

 electric furnace, in which heat was generated by one of his 

 dynamo-machines, and of such intensity that a pound of 

 broken files placed in a cold crucible were melted and poured 

 into a mould in fifteen minutes. 



By the introduction of the principles of the microphone 

 into the transmitting part of the telephone, this instrument 

 has become a practical success, and not only is it already in 

 constant use over short circuits in several parts of Mel- 

 bourne, but it is quite probable that it will soon become as 

 widely adopted and convenient as a means of communication 

 as it is in America. 



The method of sending two or more telegraph messages 

 simultaneously on a single line, called the " duplex or 

 quadruplex system," has been successfully established, and 

 Sydney and Melbourne are now communicating with each 

 other on the duplex system. 



A new era in photography appears to have set in, and the 

 old collodion process, by which so much beautiful work has 

 been done, seems likely to be entirely superseded by what is 

 known as the gelatine or emulsion process. In this method 

 the sensitive chemicals are mechanically combined with pure 

 gelatine, and extremely thin films of this are dried on glass 

 or some other impervious surface, and in this state they will 



