May 25, 1857.] USEFUL INVENTIONS. 421 



then wish every success to this gigantic project, by which, com- 

 bining the discoveries of Wheatstone with the ingenious contrivances 

 of Morse and Whitehouse, the Anglo-Saxon race is determined to 

 show, that not the broad or deep ocean can really separate the 

 two great families of the same race and lineage. 



Free-Revolver Stand. — A most ingenious invention, and one which 

 must prove of great use to seamen, having been made by Mr. Piazzi 

 Smyth, was recently tested by that skilful astronomer in his out- 

 ward voyage to examine the natural phenomena on the Peak of 

 Teneriffe, which has just been alluded to. This trial demonstrated 

 the entire efficacy of his newly mounted " Eevolver stand for 

 steadying a telescope at sea." 



Notwithstanding the excessive rolling and pitching of the vessel, 

 he kept the sea horizon in one unvarying position in the field of the 

 telescope long enough for several persons to observe it in suc- 

 cession. The only addition required was a remedy for the third 

 element of motion, arising from the azimuthal yawing of the ship's 

 head, and this his mind immediately suggested to him for con- 

 sideration during a subsequent voyage. 



New Geometrical Projection of two-thirds of a Sphere. — Our associate 

 Colonel James, the Superintendent of the Map Office, has pre- 

 sented to us a copy of his new geometrical projection of a sphere, 

 and in an accompanying letter has explained the manner in which 

 the projection is made. 



Its peculiar feature consists in the fact, that by it we are enabled 

 to represent two-thirds of the surface of the globe in a strictly 

 geometrical projection, much in the same manner that a hemisphere 

 is represented in the stereographic projections ; but as two-thirds 

 of the surface of the globe includes the entire continents of Europe, 

 Asia, Africa, and America, and indeed all the habitable regions of 

 the globe, with the exception of part of Australia and some of the 

 islands in the Pacific, this projection gives a more accurate re- 

 presentation of the relative position of every portion of the habitable 

 globe (with the above exceptions) than any other, and as the circles 

 of the parallels of latitude, down to the parallel of 47°, are complete, 

 the circumpolar regions are very accurately represented. Availing 

 himself of this latter advantage in his new projection. Colonel James 

 is now having maps of the stars made on it, in which the circum- 

 polar stars will appear in their true relative positions to each other 

 and to the other stars, which will be included in the same map. 



This projection of our Earth will be found of great use in many 



