252 Hassler''s Repeating Theodolite. 



from the accident, has, with every other symptom of disease, 

 wholly disappeared. 



Allow me to acknowledge my obligations, for the re- 

 spectful sentiments, you have done me the honor to express, 

 in your last,* and on former occasions; which, in truth, 

 I cannot too highly appreciate, as coming from the founder 

 of a Journal, which is dispensing the fruits of science, to an 

 ungrateful community ; and which, though suffered to ex- 

 pire, will have erected, by its kindly influence, on the mora! 

 condition of man, a monument imperishable. 



I am, dear Sir, truly and respectfully yours, 



Joseph E. Muse. 



Art. VII. — Hassler''s Repeating Theodolite. 

 Notice of this instrument, in a letter to the Editor, dated New York, May 8, 1829. 



Sir — Permit me to make known, through your useful Jour- 

 nal, an improved repeating theodolite, by Mr. Hassler, who 

 is so well known both in this country and in Europe, for his 

 improvements on repeating and reflecting circles and theo- 

 dolites. This instrument has just been constructed, for the 

 first time, by Mr. Richard Patten, instrument maker of this 

 city, for the exploring expedition, and will be found on exam- 

 ination as near perfection in principle, as it is possible to arrive 

 at ; compensating not only the faults of workmanship, but the 

 errors of observation. Its adjustments are those of the re- 

 peating circle and theodolite, so well and fully described by 

 the inventor, in his paper on the coast survey. An inspec- 

 tion of the drawing with the annexed description, I hope 

 will make the superiority of this instrument well understood. 

 It will be seen that its proportions are well adapted to give 

 it solidity, and all its adjustments permanency. The cen- 

 ters, collars and axis, are all of bell metal truly turned. The 

 triple center work, of different sized cone?, moving in each 

 other, is a very great improvement, giving greai solidity and 

 little fiiction, and making the instrument susceptible of any 

 number of repetitions. I should be doing great injustice to 



* AUuding to the letter to which this is an answer : I should hardly have 

 been wiSliiig to allow the above paragraph, (of certainly too partial commenda- 

 tion,) to remain, had it not been for the present posture of affairs, as regards 

 tlie prosperity of this Journal. — Ed. 



