374 TRANSACTIONS OF THE 



in building the iron vessel for carrying Dr. Livingston on Iils mission ta 

 the very heart of the almost unknown regions of Africa. 



ECONOMY OF STEAM. 



All the steam engines now extensively in nse, are practically, in fact^ 

 Watt's engines, more or less developed and improved, and it appears that^ 

 in some instances, an economy has been now attained that the consumption 

 of coal is only from two to two and one-half pounds per hour per indica- 

 ted horse power ; and theory shows that this is almost the greatest economy 

 we can arrive at ; and if we want to economize further, we must introduce 

 some new principle, such as the use of superheated steam, (the I'ate Mr, 

 Frost's stame,) or heated air, which is analagous to it, inasmuch as it can 

 be worked at a high temperature without, attaining a dangerous pressure I 

 (Quere.) The theory of this is now well understood , and the only diffi- 

 culty that exists, is as to its convenient practical application. 



[London Artisan. April, 18&8.] 



INSTITUTION OF CIVIL ENGINEERS. 



Sawyer on "The Self-acting Tools employed in the construction of 

 Steam Engines," &c. 



The new mode of forging rivets for boilers ; making a ton of well formed 

 rivets, exactly alike^ in ten hours, and apparatus for forging nuts exactly. 



Mr. Richard Roberts has made his Jacquard or Multifarious Perforating 

 Machine, and it is now employed at the Canada Works, Birkenhead, for 

 punching the boiler plates for making the Victoria bridge over the river 

 St. Lawrence, It punches 72 holes in each plate of ten feet long and 3| 

 wide and 5-l(5th of an inch thick ; does 90 such plates in 10^ hours by 

 one mechanic, three laborers and one boy. The same work by hand takes 

 4 men to work with the templates, and 8 men at the machine, and do much 

 less work in a day than the machine does. 



It was stated that great care should be taken in using the rivet machines^ 

 as, if undue pressure is employed, the rivets are too much compressed ;: 

 and instances were given in which the plates were split in riveting through- 

 out their length. The cunning hand of man is truly admirable ! A good' 

 workman would not do that. 



ELECTRO-MAGNETIC ENGINES 



are under consideration ; and to show that these are not mere matters of 

 speculation, for they are actually used in France for driving small and 

 delicate machinery, for which they are well adapted, being clean, easily 

 managed and cool. But they cost more than steam engines. To -produce' 

 a given total amount of energy, it consumes 32 lbs. of zinc for every six 

 pounds of coal that a steam engine consumes. 



COLORING MATTER FROM COAL TAR, GUANO AND 



GRASS. 



London, April, 1858. 



The products of coal tar have long been looked to as a valuable source 

 oi Ji7ie dyes and colors, and we are now enabled to show that this view ha 



