230 THE AMERICAN MONTHLY [Au 



tripod, is in some respects preferable to this latter form 

 in the greater facility afforded forgetting at the sub-stage 

 adjustments when the microscope is used vertically. The 

 limb is of the "Jackson" form with lever fine adjustment, 

 than which we have found none more sensitive or servica- 

 ble. Each revolution of the milled head gives a move- 

 ment of 11 millimetres (1-225 inch). The body has two 

 draw-tubes, giving a variation of tube lengtii from 120 

 to 250 millimeters, thus enabling objectives corrected for 

 both the short and the long tube to be used at will. Both 

 draw-tubes are graduated in millimeters, and the lower 

 one is actuated by rack and pinion ; a very useful addi- 

 tion when adjusting objectives so as to correct them for 

 diflfereut thicknesses of cover-glass, especially in view of 

 the growing tendency to make such corrections by this 

 means instead of by the provision of a correction collar to 

 the object itself. The body is of a large diameter that 

 should lend itself to photography, and the eyepieces are 

 of the new R. M. S. No. 3 standard size. There is a me- 

 chanical stage giving a movement of 25 millimetres in 

 either direction, and graduated to half millimetres, and 

 the stage is capable of rotation for about 280°. The top 

 plate is provided with three adjustable stops for 3 inch x 

 1 inch and 3 inch x IJ inch slides with a view to greater 

 facility in recording positions, and if required a large flat 

 plate is available. The substage is of the usual form with 

 centering screws, coarse and fine adjustments, the latter 

 being exceptionally neat and so conveniently placed that 

 both adjustments can be controlled without shifting the 

 hand. There are the usual mirrors. All the fittings are 

 Bprung, and have adjusting screws to compensate for wear. 

 The price of the stand alone, without case, is $83.00. 



Ova of Lepidoptera. — Recently we had the opportu- 

 nity of carefully examining some hundreds of water-color 

 drawings of British Lepidoptera. They were the work of 

 Mr. E. Wheeler, of Queen's Road, Clifton, near Bristol, 



