MECHANICS AND USEFUL ARTS. 125 



or pliable material, is used to give the impression ; said chamber being fur- 

 nished with a tube and plunger, and the pliable bottom or side of the chamber 

 serving as a tynipan. By applying pressure to the plunger, an equal amount 

 of pressure is transmitted by the water or fluid to every part of the tympan, 

 and by using a small plunger an immense pressure may be obtained with a 

 small expenditure of power. 



Litliograpldc Printing Press. In an unproved French lithographic printing 

 press the following novelties are embraced. A sliding carriage, which travels 

 over the stone or other engraving, and carries along the printing scraper, to 

 take off the impression, and which is moved to and fro by a crank on a shaft ; 

 a loose tilting frame which carries a plate and sheet to he down upon the 

 paper that has been put upon the plate to be printed, from the printing scraper 

 passing over the sheet with the necessary pressure, and the loose tiltmg-frame 

 being raised or tilted up by the said carriage at the end of each backward and 

 forward stroke, so as to allow of putting a fresh sheet of paper on the stone 

 or plate engraved upon. 



BURT'S SOLAR COMPASS. 



An invention presented to the Franklin Institute hi 1835, improved and 

 again reported on in 1840, receiving a medal at the London Fair in 1851, and 

 used hi public surveys for fifteen years, can but with extreme difficulty be 

 termed a new invention. The solar compass seems, however, to have but 

 recently been prepared to attract the attention it deserves, and a very brief 

 notice may not be inappropriate. 



The compass is the invention of Mr. "Win. A. Burt of Mount Vernon, Michi- 

 gan, and seems to occupy a kind of intermediate place between the old Kit- 

 tenhouse compass and the Theodolite of the present day. It is designed for 

 extensive land surveys, and is greatly superior to the theodolite in the facility 

 with which it is used. As compared with the more ordinary compass, in all 

 mineral regions and in localities where the aberrations of the needle are a 

 source of frequent difficulty, it appears almost indispensable. 



It may be described as a magnetic compass, with every, facility for levelling 

 and adjustment, and provided additionally with movable arcs and simple 

 mechanism by which whenever the sun is visible, and its declination known 

 (which may be found hi any nautical almanac), the time of day, the latitude of 

 the place, the angle made by any point with the true meridian, and conse- 

 quently the correct bearing thereof, may be determined by inspection with the 

 minutest accuracy. Its easy adjustment and entire reliability, enable it to 

 supply the want long felt by the practical surveyor. 



DUMERY'S METHOD OF CONSUMING SMOKE. 



Among the prizes awarded during the last year by the French Academy, 

 was one to M. Dumery for a contrivance for consuming the smoke of chim- 

 neys, which has worked with complete success in a series of comparative 

 experiments under the inspection of a commission of the academy. 



M. Dumery, in place of throwing hi the fresh coal by the door of the fur- 

 nace upon the burning combustible, as in ordinary fires, causes it to enter 



