76 ANNUAL OF SCIENTIFIC DISCOVERY. 



BUTTON'S PATENT CLOCK. 



THIS clock, invented by Mr. Hutton, of England, and contributed to 

 the Great Exhibition, has a new compensation glass pendulum, and a 

 barometric contrivance, to prevent the error arising from the changes 

 in the density of the atmosphere. The metallic compensation is effected 

 ivilhout any friction, by the ascent and descent of two spring levers with 

 three adjustable weights, and which lengthen or shorten as they rise or 

 fall. The mode of compensating is regulated by a screw in the top of 

 the ball, which, in case of heat, is moved towards the centre of motion of 

 the spring lever, or in the contrary direction in case of cold. The glass 

 rod is attached to the pendulum-spring, by means of a screw cut on it, 

 and below, a glass regulating-nut works into a glass screw, cut on the 

 bottom of the pendulum-rod. The compensating wires being very 

 small, a simultaneous action is ensured at each change of temperature. 

 In the barometric contrivance, the ivory piston rests on the mercury, 

 thus counterpoising the air-vanes, so that \vhen the barometer is low, 

 it causes them to approach the plane of the pendulum's motion, and 

 raises them, on the contrary, when the barometer is high ; thus the 

 mechanical resistance to the pendulum is increased or decreased ac- 

 cording to the density of the atmosphere. 



SELF-ADJUSTING PENDULUM. 



A NEW and economical self-adjusting pendulum was shown at the 

 Great Exhibition. Instead of the ordinary rod, by which the ball is 

 suspended, being attached to its centre, a bar is secured to the side of 

 the ball, and a wooden rod fixed thereto ; so that the elongation or 

 shortening of the rod, by change of temperature, turns the ball on its 

 axis, and thus preserves accurately the distance between the points of 

 suspension and oscillation respectively. 



CHEAPNESS OF AMERICAN CLOCKS. 



To such perfection has the manufacture of clocks been carried in 

 Connecticut, that time-pieces, warranted to keep good reckoning, are 

 sold for sixty cents, at wholesale, and one dollar, retail. The works 

 are all of brass, made by machinery. At the manufactory of Mr. Je- 

 rome, New Haven, 800 per day of these articles can be produced. 

 Wooden clocks, but comparatively few years since, sold for from ten to 

 twelve dollars. 



ATMOSPHERIC CHURNS. 



DR. PAGE, of the Patent Office, in his report for 1849-50, states that 

 during that year tAventy-one applications were made for patents on 

 churns. " Most of these were styled atmospheric churns, and I have 

 never witnessed such a mania upon any one invention. The first im- 

 pulse seems to have been given by the grant of a patent for a churn, 

 in which there were boxes upon opposite sides of a common revolving 



