lAJe, and writings of Count Mumford. xvii 



of temperature produced in Ihe fluid during the operation. A steel 

 borer pressed against the metal of the gun, with a force equal to 

 itn thousand pounds, while the gun revolved 33 times in a min- 

 ute ; caused the water in the box, amounting to 18 or 19 lbs. to 



■ 



boil in 2 hours and an half. The heat thus produced was as 

 ^reat as would have been given out by nine large wax can- 

 dles burning all the time. The Count, concluding that no change 

 took place in the specific heat of the metal, nor was any heat de- 

 rived from the air; adopts the opinion, which has many sup. 

 porters at the present day, that heat is a vibratory motion of th« 

 particles of a substance, and not a substance sui generis 

 With a view to increase the comfort and usefulness 

 ing, he made experiments to determine the relative quantities of 



of cloth- 



e absorbed from the atmosphere by 

 that purpose. He found that wool 



different materials in 



from the atmosphere than any substance used in clothing, and 

 concludes that woollen clothes, such as flannels, worn next the skin 

 greatly promote insensible perspiration, independently of their su- 

 perior warmth. He considers the practice of wearing flannel to 

 be highly salubrious not only in cold, but also in warm climates. 

 In an inquiry concerning the weight ascribed to heat, he found 

 that bottles of different fluids, as mercury, alcohol and water, re- 

 remained in equilibrium during great changes of temperature, not- 

 withstanding the very unequal quantities of caloric, which they 



must have lost, owing to their diffi^rent capacities for heat. His 

 experiments show that a quantity of heat equal to that which about 

 ten ounces of gold would require to raise it from the temperature 

 of freezing water to be red hot, produces no sensible effect upon 

 » balance capable of indicating so small a variation of weight »• 



e 



