MAGNIFYING POWER OF SHORT SPACES. 27 



young Sagitta will, therefore, very possibly be found to re- 

 semble one of the Tardigrada, the rudimentary feet with their 

 hooks being subsequently thrown up to the region of the head 

 as they are in Linyuatula." 



Krohn, with much hesitation, is inclined to regard it as 

 belonging to the Annelid group, with which it would certainly 

 at present appear to exhibit a very probable relationship. 



On the Magnifying Power of Short Spaces illustrated by 

 the Transmission of Light through Minute Apertures. 

 By John Gorham, M.R.C.S.E., &c. 



Having described in the former papers the appearances 

 observable when pencils of light from small circular apertures 

 are partially intercepted by certain opaque or transparent 

 objects of definite shape and size ; and having shown that 

 whether shadows or illuminated spaces are thus used, they 

 serve to exemplify the magnifying power of short intervals 

 existing between the organ of vision and the object to be ex- 

 amined, inasmuch as they occupy some position in space, and 

 have a certain^brw, qualities which pertain to them in common 

 with all substances appreciable by the sense of sight, we pro- 

 ceed to notice the phenomena which result when exceedingly 

 narrow linear apertures are substituted for those of a circular 

 form. In conducting these investigations it was not unreason- 

 able to suppose, a priori, that if the size, the quality, and the 

 position of the object to be examined, the direction and the 

 intensity of the light which was used, the sensitiveness and 

 immediate response of the pupil of the eye to the minutest 

 variation in the quantity of light impinging on the retina, and 

 the refracting qualities of the transparent portion of the visual 

 organ, were each and all taken into account, so that a nice and 

 delicate adjustment of the eye to the light, and of the light as 

 well as of the size of the objects to the eye could be insured, 

 appearances perhaps beautiful, doubtless uncommon, and cer- 

 tainly interesting to the physiologist might be fairly antici- 

 pated. Such anticipations, have been so far realized as to 

 present a strong inducement to prosecute the subject with a 

 legitimate prospect of still greater success. 



It is obvious that the phenomena which have occupied our 

 attention are chiefly due to the formation of shadows. For 

 when a divergent pencil of light proceeding from a small cir- 

 cular perforation in a card falls upon the eye, and when a 

 small object either transparent or opaque — a transparent cross 

 on a black ground, or a black cross on a transparent ground, 



