588 



TRANSACTIONS OF THE 



Extracts from works recently received by the American Institute. 

 RAILROAD BRAKES. 



A Frencli engineer, Mon. Cundot, has made a new brake. He 

 makes liis brakes act upon the rails in series^ instead of the 

 wheels. It is said he stops a train moving nearly forty miles an 

 hour in the space of 440 feet, without perceptible shock to the 

 passengers. We shall probably hear more of it soon, if it has 

 these valuable properties. 



The incalculable value of a perfect system of brakes, is now 

 every where admitted. When we found that we had in point of 

 speed out-flown the swiftest birds, it instantly became a life ques- 

 tion, how to stop that arrow 1 



We have good ground for believing, that if that can be properly 

 done, it will issue from American brains. 



CALCULATING MACHINES. 



It is singular that the exact sciences may be mechanically 

 served, from the most simple original notation to the vast extent 

 of numbers, ten places of figures. 



The Paris Moniteur says, " Mr. Thomas, of Colmar, has lately 

 made his finished improvements in his calculating machine, 

 "which he calls his Arithmometer (measurer of numbers,) on 

 which he has worked thirty years and more. In the seventeenth 

 century, Leibnitz.^ the transcendental philosopher, Pascal, tried to 

 make such a machine, but failed. Later, Diderot tried it, and 

 also failed. Thomas' Arithmometer is used without any trouble, 

 and there is no possibility of error in addition, subtraction, mul- 

 tiplication and division ; also for extraction of square, involu- 

 tion, resolution of triangles, &c. A multiplication of eight figures 

 by eight, is done in eighteen seconds. Division of sixteen figures 

 by eight is done in twenty-four seconds. The square root of six- 

 teen figures in one minute and a quarter, and the calculation 

 jjroved. 



The working of the machine is very simple. To raise or to 

 lower a nut screw, turn a winch a few times, and by means of a 

 button to slide off a metal plate from left to right, or from right 

 to left, is the wiiole secret. It is quite portable, and already in 

 use in many great financial establishments, with much economy 

 of time. This discovery is of great importance, so much so, that 

 as yet we cannot measure the amount. 



Mr. Tillman had no idea of the profitable use of contraction 

 and expansion of metal as motive power. Nor would the alter- 



