Prof. Page on Electro-Magnetism as a Moving Power. 163 



4. The proportions of the hehces were approximately tested; 

 though much remains unsettled yet upon this important point. 



5. The advantage of keeping up the magnetism in the axial bar 

 was most satisfactorily tested. 



6. Various modes were tried of reversing the motion of the en- 

 gine, and with success. 



7. Various kinds of cut-ofF (which is the most critical and im- 

 portant point in the construction of the engine) were tried. 



8. The operation of closed circuits and secondary currents was 

 tested by a number of experiments, requiring great care and ac- 

 curacy. 



9. The best working velocity of this engine, and its absolute 

 power with a given battery, was fully tested. 



10. The ratio of the increase of power, with an increase in the 

 quantity of the current. 



1 1 . The values of different kinds of metal in forming the cut-ofF. 



12. Various mechanical points of construction, supposed to have 

 been incompatible with the exhibition of this power, were put to a 

 practical test. 



Various other minor points also were the subject of experiment, 

 which will be communicated hereafter. 



A second model, of small size and somewhat rude construction, 

 was also made, with a view of testing a new arrangement of the 

 axial bars. 



Experiments were then commenced upon a larger scale, with a 

 view to determine whether the same proportion of power could be 

 obtained from large as from small engines, this being the principal 

 question in view at the time of the grant of the appropriation. 



With a view to facilitate the construction of helices of large size, 

 a machine which had long been in contemplation was made at a 

 considerable expense. The work was done at the Navy Yard in a 

 creditable manner, and the machine performed its work well, turning 

 out entire helices of copper wire, of large size, from straight bars. 

 But before I had proceeded far, a discovery was made in reference 

 to the helix which rendered the machine useless, for the present at 

 least. 



A number of large hehces were then constructed of various sizes, 

 and suitable bars of soft iron prepared, corresponding to the helices. 

 Hollow and solid bars were prepared, from two inches to eight 

 inches in diameter, and generally three feet in length. Some bars 

 of four and five feet in length were also prepared. The bars were 

 all worked at the Navy Yard, and at a considerable expense, as they 

 were required to be of homogeneous metal, accurately turned and 

 bored. 



With these bars and helices a multitude of experiments were per- 

 formed and recorded, and these were kept up day after day for 

 about two months. My ofhcial duties as Examiner in the Patent 

 Office left me only the evening of each day for operation ; and, 

 under su^h circumstances, you will readily appreciate the difficulties 

 and disadvantages under which I have laboured. My own zeid has 



M2 



