208 



Means by which this Uniformity of Continuous Motion has been 



attained. 



1. Screw axes for progressive motion, to generate a spiral, have 

 been rejected. 



2. The progressive motion is made by the registering head bearing 

 the magnet and stile, or puncturing pen, and travelling on rails like 

 the V bars of a turning lathe. 



3. The progressive motion of this registering head is not derived 

 from the rotation of the cylinder, but that head moved independently 

 by means of a little clock being attached to running cord of the 

 same. 



4. The puncturing pen acts perpendicularly to the surface of the 

 cylinder, and having a joint by which it yields to the cylinder's mo- 

 tion, it offers no retarding drag. 



5. The cylinder is, in all respects, left free to revolve, and its fric- 

 tions, including all of its wheels, revolve or return, at short intervals, 

 into themselves. Incidentally this punctured sheet, by being inter- 

 posed between the eye and a candle, and moved rapidly in curves 

 and waves, exhibits lines in a curiously figured manner, showing the 

 candle flame as a screw, sometimes right handed and sometimes left 

 handed, &c. 



Very respectfully yours, 



JOHN LOCKE. 



Mr. Justice laid upon the table for inspection, two daguerreo- 

 types of the moon, taken by Mr. Whipple, of Boston, through 

 the refracting telescope of the Cambridge Observatory; one 

 representing it in its first quarter, the other when nearly at 

 the full. 



He mentioned, that to those acquainted with the different localities 

 of the moon's surface, the accuracy of the pictures is highly gratify- 

 ing when placed in the direct rays of the sun, and viewed through a 

 magnifying lens. Hitherto any attempt to portray the scenery of 

 the moon by drawings, has been entirely unsatisfactory in conveying 

 a true impression of its diversified appearance through a telescope; 

 but he now hoped, from the constant improvement in the art of da- 

 guerreotyping, that an enlarged picture of the moon's disc may be 

 obtained, from which engraved maps might be made, so that the se- 

 lenography of our satellite may be studied in our schools, in conjunc- 

 tion with the geography of our own planet. 



