38 The Ruins of Gopan. 



off, is very ingenious, and brings us back to the microscopic 

 neutral tint reflector with which we started. This re- 

 flector enables drawings to be made much larger than the 

 actual image which the microscope transmits to the eye. 

 Suppose, for example, the image represented an insect one 

 inch long, and the draughtsman tried to sketch it with a long 

 pencil on a sheet of paper placed on the floor, he would have 

 to make a picture on the floor as big as an object must be to 

 equal in apparent size a far smaller object nearer the eye. This 

 may be made plain by a diagram, and plainer by an experi- 

 ment. Take, for example, a sixpence, and hold it at such a 

 distance from the eye that its diameter exactly equals that of 

 a large picture across the room. Then the sixpence, at so 

 many inches, and fractions of an inch, from the eye, looks as 

 broad as the great picture so many feet off. For a second 

 illustration, hold the sixpence steadily in front of the eye, 

 about six or eight inches off, and let some one else stand by 

 the wall and make a mark corresponding with the circular 

 space the sixpence hides. In this case the great circle, so 

 many feet or yards off, is equivalent to the little sixpence at 

 six or eight inches off. In the instance of the imao-c reflected 

 by the neutral tint glass used with the microscope the pencil 

 was employed to trace out an outline that would be equivalent 

 to the reflected image seen much closer, and in Mr. Brown's 

 enlarged ghosts, the optical image takes the size of his plates, 

 as they appear at a convenient distance from the eye, but they 

 seem as big as they would look if drawn on a larger scale on 

 the wall on which they are fancied to appear. 



THE RUINS OF COPAN. 



In our number for May, 1863, we gave a beautiful view of an 

 enormous sculptured monolith from the pre-incarial ruins of 

 Tin Snanaco in Bolivia, formerly Upper Peru, accompanied 

 by a paper, in which Mr. Bollaert collected together the 

 rery little thai is known concerning this kind of work. 

 The whole subject of American antiquities is under a dense 

 cloud. We can only make rude guesses concerning the 

 dates of the eemarkable remains, or of the extincl and for- 

 11 people by whom they were executed. It. is how- 

 ever of importance thai accurate representations should 

 l»e preserved of the principal objects ^l' interest, and lor this 

 purpose photography is of great value, and fortunately admits 

 of reproduction at a vi'vy moderate juice. The Tia Euanaco 

 ruins form a portion of numerous works, extending over a con- 

 siderable geographical area, and all bearing evidence of having 



