242 Intelligence and Miscellaneous Articles. 



screws working in the cast-iron frame which is bolted to the stone 

 floor of the turbine-pit. In the Tremont turbine this floor is of 

 wood, and in plate 1 the steady-pin is marked ' I.' 



"The pieces sent are marked Nos. 1 to 5. No. 1 is the portion 

 of the steady-pin which was nearest the shaft ; No. 2 the other ex- 

 tremity of the same pin ; Nos. 3, 4, 5 the three pieces of case- 

 hardened iron forming the box, with portions of this steady-pin at- 

 tached. You will at once perceive that this steel has been partially 

 fused, and can thus account for its attachment to the iron. 



" The facts are, that on noticing some irregularities of motion on 

 the part of the wheel, it was stopped, and the water pumped from 

 the pit until the floor was bare. Inspection showed that the follow- 

 ing-screws had not done their duty uniformly ; and the three pieces, 

 Nos. 3, 4, 5, no longer preserved their proper relative positions, nor 

 allowed free play to the steady-pin. The consequence was, an 

 amount of friction causing heat sufficient to fuse steel, although the 

 latter was immersed 3 feet deep in a raceway 10 feet wide, through 

 which was passing 75 cubic feet of water per second. 



"A similar accident happened thrice to our turbines, which are 

 now, ho\vever> safely guarded against such mishaps." 



There are two points in connexion with these facts to which I 

 wish especially to call attention. In the first place, the weight of 

 the wheel did not rest upon the surfaces of friction. The three pieces 

 of case-hardened iron in their displaced position acted simply as a 

 brake upon the revolving shaft ; so that the heat must have resulted 

 wholly from the destruction of mechanical motion : the immense 

 moving-power of the wheel, instead of being directed wholly into 

 its appropriate channel, was in part transformed into that mode of 

 atomic motion called heat. In the second place, the temperature 

 attained was at least the welding-point of iron, and this, too, although 

 the heated metal was immersed in a stream of flowing water. It is 

 undoubtedly true that the spheroidal condition of the water would 

 greatly retard the loss of heat ; but still the loss must have been 

 exceedingly rapid. Now the loss, even at the highest temperature 

 attained, must have been fully supplied by the heat generated during 

 the same time ; and this must, therefore, have been evolved with 

 equal rapidity at the surfaces of friction. No change in the mole- 

 cular condition of the iron, and no abrasion of the metal, is at all 

 sufficient to account for this continuous, prolonged, and immensely 

 rapid evolution of heat ; and the facts force upon us the conclusion, 

 that the destruction of mechanical motion is the one and only efficient 

 cause. Moreover, if we admit the generally received principle of 

 mechanics, that motion cannot be annihilated, the conclusion that 

 heat is a mode of motion is equally irresistible. Lastly, it is evident 

 that the facts here stated perfectly accord with the well-known 

 experiments of Rumford and Davy ; only, since the moving-power 

 of the Merrimack turbine is so much greater than that employed by 

 these distinguished experimentalists, the results which I have had 



