MEMOIR OF DANIEL TREADWELL. 403 



powers of engines oC difleient dimensions and forms of construction j the compara- 

 tive power of the same engines using steam of a given elastic force when running 

 at different velocities ; the quantity of wood required to produce a given power ; 

 the resistance of the load when passing upon a horizontal plane, and upon ascents of 

 different inclinations, and likewise the effect of the curves of the railway in increasing 

 the resistance ; and any other f;icts important to the constructive arrangement or 

 management of railroads or locomotive engines. These investigations were made the 

 subject of an elaborate report, in March, 1837, which will be found in Appendix 11. 



In 1838, Professor Treadwell was appointed by the Secretary of the Treasury of 

 the United States, together with Dr. Jacob Bigelow, Alfred Greenough, and William 

 Sturgis, on a commission for the purpose of superintending the experiments in 

 relation to lights in light-houses. But this appointment was declined. 



Professor Treadwell still retained his connection with the Boston Hemp and 

 Cordage Company, which grew out of the successful operation of his machines ; he 

 was its agent for conducting a large business in spinning the hemp, in manufactur- 

 ing cordage, and in constructing machines for the Government, and for many of 

 the large manufactories. Indeed, it was the income from these sources that enabled 

 him to accept the Rumford Pi-ofessorship, from the funds of which he received but 

 about eight hundred dollars a year. 



In 1840 he had already been considering the practicability of constructing 

 cannon of greater strength, and consequently of greater calibre, than those in com- 

 mon use. Count Rumford had long before turned his attention in the same direc- 

 tion, but his experiments were limited to the use of cast iron, modified by a new 

 method of casting by which its tenacity was very much increased. The thoughts 

 and labors of the Rumford Professor were destined from this time to be directed to 

 the same subject for the greater part of his active life. He had by long experience 

 in the manufacture of machinery learned the properties of metals ; he had studied 

 the forces to which they are subjected when used as materials for cannon, and saw 

 the advantages to be obtained by the substitution of wrought iron and steel for 

 bronze and cast iron. 



In 1845 he published " A Short Account of an Improved Cannon." * The fol- 

 lowing extracts will show the course of reasoning which led to the invention of the 



• This account was reprinted in 186.5. It was translated into French in 1848, with the title, "Notice suceincte 

 sur un Canon Perfcetionnc et sur los Procedes ineclianiqiies employes ?i sa Falirication, par Daniel Treadwell. Tra- 

 duction de M. Kieffcl, Professcur de Sciences appliquees a I'Ecole d'Artiilerie de Vincennes." Paris, 1848. 



