ASTRONOMY AND METEOROLOGY. 377 



let, star in Orion, far the most deeply colored object I have yet seen. 

 Its mean place for 1850 is, R. A. 4 h> 52 m - 45 s - , N. P. D. = 15 2'." 



Mr. Fletcher says, in relation to Pollux, which Capt. Smith, in the 

 Celestial Cycle, remarks has been suspected of varying in lustre, since 

 it is recorded as having at times been brighter than Castor: "At 

 the moment I am writing, Pollux is obviously brighter than Castor, 

 and I think it brighter than o Ursee Majoris, at any rate, fully as 

 bright." 



Mr. G. S. Spreckley writes : "On my voyage from Suez to Pe- 

 nang, my attention was excited by the unexpected splendor of 77 Argus, 

 which is now a large first magnitude, surpassing every other star in 

 the constellation except Canopus. Seen with the naked eye, or with 

 a glass, there was a manifest difference in color between the rays of 

 light from its S. W. and from its N. E. position, the former being bril- 

 liant red, and the latter bluish-green. Is it a double star? ' 



SPRING-GOVERNOR. 



AT the meeting of the American Association, at New Haven, a 

 new machine was exhibited, designed for producing uniform continu- 

 ous motion, for which the name of the Spring-Governor has been pro- 

 posed. The apparatus was invented by the Messrs. Bond, of Cam- 

 bridge. It consists of a train of wheels communicating with a fly- 

 wheel, intermediate between which and the motive power is a dead 

 beat escapement, connected with a half-second pendulum. The con- 

 nection between the escapement-wheel and the rest of the machinery 

 is through a spring. The elasticity of the spring allows the motion 

 of the circumference of the escapement-wheel to be arrested at every 

 beat of the pendulum, while the rest of the train continues moving. 

 By this means all changes in the motive power are effectually control- 

 led, and a rotation perfectly continuous and uniform secured in the fly- 

 wheel, so that the moving force may be increased without affecting its 

 velocity. The principle may be applied to various forms and kinds 

 of machinery. The design, in the present instance, was to secure an 

 invariable motion to the recording surfaces employed in the electro- 

 telegraphic operations of the Coast Survey. A clock of this description 

 is to be constructed for the great equatorial of the Cambridge Observa- 

 tory. 



DOVE'S MAPS OF THE ISOTHERMAL LINES OF THE GLOBE. 



PROF. DOVE has published some maps of the monthly isothermal 

 lines of the globe, the object of which is to show the mean tempera- 

 ture, on Fahrenheit's scale, of every month in the year, at 900 stations 

 on the globe. They ha.ve been constructed with great labor, on the 

 basis of observations extending over a series of years. Among his re- 

 sults, the London Athenaum for July gives the following : Dividing 

 the globe at the meridian of Ferro, and computing the temperature 

 of the parallels east and west of that meridian at every ten degrees of 

 latitude, it is found (with the exception of the latitude of 70) that the 



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