192 EDITORIAL ARTICLE. 



lens of 5 or 6 inches focus ; if one of longer focus be used, 

 the dispersion of light becomes too great to ensure an accurate 

 representation. When the tree or shrub is well illuminated 

 by the solar beams, the lens should be presented towards it, 

 at a distance varying of course with the height of the object. 

 A piece of card-board should then be placed in the box, a 

 little beyond the true focus of the lens, and the former moved 

 until a well-defined bright image of the tree &c. is formed on 

 the card, of course in an inverted direction. The box is then 

 to be placed on any convenient support in this position, and 

 a piece of the prepared paper fixed on the card, the lid of the 

 box is then to be closed, and the whole left for half an hour, 

 at the end of which time a beautifully accurate outline of the 

 object will be found on the paper, which is then to be render- 

 ed permanent in the usual manner. It is obvious that this 

 plan is unavailable on a windy day, on account of the branch- 

 es of the tree &c. being continually moving, so that it is of 

 far less use to the botanist than the above described process 

 for obtaining drawings of small specimens. 



Various other applications of this paper will suggest them- 

 selves to the minds of naturalists, but having far exceeded my 

 intended limits, I conclude by subscribing myself, 



Yours very faithfully, 

 Golding Bird, M.D. 

 22, Wilmington Square, 



March 25th, 1839. 



magazine of natural history. 



APEIL, 1839. 



The Memoir of Madame Power upon the Paper Nautilus and the ce- 

 phalopodous animal as yet its only known occupant, originally published 

 in the Proceedings of the Academy of Catania, is concluded in our pre- 

 sent number : and to those who feel at all curious upon the subject, the 

 history of this lady's researches will furnish matter of extreme interest. 

 To us it appears that the observations of Madame Power, in connection 

 with evidence subsequently drawn from materials in her possession, all 

 but demonstrate the relation between the poulp and the argonaut-shell, 

 to be one of necessity and not of convenience. At all events, this long-dis- 

 puted question will henceforward hold a position very different to that 

 which it has for a long period occupied ; for it will hardly now be assert- 



