252 Curve described by a Movable Pulley. 



32. To Dr. Bache and his officers of the coast survey, belongs 

 the credit of systematic and persevering efforts to determine lon- 

 gitude telegraphically: and incidentally their efforts to improve 

 the means of such determination have been the cause of my ma- 

 king the invention under consideration. Mr. Walker is enthusi- 

 astic ; his manner and conversation are exciting, and he was very 

 prompt to perceive, appreciate, and make known, the advantages 

 of the printing method of observing. His invention of a tel- 

 escope with cross hairs multiplied in proportion to the rapidity 

 with which observations can be made by my chronograph, is evi- 

 dently a valuable one. Indeed in that which is the special de- 

 partment of Mr. Walker, the astronomical part of the report, it 

 is unnecessary for me to say that he has done himself his usual 

 credit. The ambiguities which I have been obliged to notice, 

 have been the result of rather a hasty use of a new term, a want 

 of a clear perception of the necessity of a closed circuit, and a 

 consequent confounding of my invention with the ordinary mag- 

 netic clocks, neither intended for printing of observations ) nor 

 possible to be used as a part even of the mechanism for that 

 purpose. 



33. At certain points I have indeed had good cause to feel 

 indignant at the course pursued towards me. Men professing to 

 be astronomers, have not only asserted their determination to 

 use my invention, not only without my permission, but without 

 giving me the least credit ; but they have endeavored by all means 

 in their power to belittle my claims, and to defeat my political 

 friends m procuring that reward from government which in their 

 opinion was merited. 



In the last point it appears they have been unsuccessful. How- 

 ever grateful it may have been to me that my friends in Congress 

 have made themselves fully and particularly acquainted with the 

 subject of my labors, and have procured from such high authori- 

 ty, a decision in my favor, still I have deemed it incumbent on 

 me thus to place in a clear light those points, concerning which 

 I had been informed there had been some misapprehension. 



Art. XIX. — On the Cvrve described by a Movable Pulley ; by 

 A. Secchi, Prof, of Nat. Philos. and Mathematics in George- 

 town College, D. C. 



It frequently happens, that many obvious facts remain uncon- 

 sidered during a long space of time, until attention is drawn to 

 them by mere chance, and I doubt whether this may not be the 

 case with the problem which I now lay before the public. It 

 is a fact, (which has been no doubt often observed,) that the 

 movable pulley when raised, describes a curve ; but I am quita 



