112 THE entomologist's RECORD. 



objective to the centre ot the focussing screen of the camera, and 

 passing centrally through the intervening portions of the microscope 

 body and the camera. This block I screwed down firmly in the 

 required position, and fixed small wooden stops at the sides and ends 

 to prevent the microscope from slipping when placed on it. 



[ then drilled a hole for the camera screw in the centre of the base 

 board, in such a position that, when the camera was screwed down to 

 it, the lens front just touched the eyepiece of the microscope, when the 

 latter was racked out to its fullest extent. It was now necessary to 

 devise some means of connecting the microscope with the camera in 

 such a way as to exclude all light except that passing through the 

 formo!', and yet to admit of focussing being done as usual. To do 

 this r obtained from an instrument maker a short brass tube about 

 lin. in length, with a screw thread cut on one end to fit the lens 

 flange of the camera. This I screwed in, in place of a lens, and then 

 made a sleeve of black velvet to slip over it, long enough to be drawn 

 over the microscope body tube, and held in place at either end with an 

 elastic band. This answered admirably, and I found that after 

 focussing an object on the stage of the microscope and then con- 

 necting the microscope with the camera, I was able to get a sharp 

 image on the ground glass of the latter with the extension at my 

 disposal, and to reduce or enlarge this by altering the amount of 

 camera extension, and then to refocus with the microscope by stretching 

 out my arm along the side of the camera while I kept my eyes fixed 

 on the focussing screen. 



This somewhat primitive apparatus answered well so far as it 

 went, but I soon determined to work without the microscopic eyepiece, 

 and set to work, therefore, to build a very long extension camera. I 

 made it |-plate size, so that the accessories I already possessed could 

 be used, and gave it a bellows 42in. long in three sections to obviate 

 sagging. I found this was a great improvement, but had, of course, 

 to get a much larger base board, and used for this an oak plank 

 5ft. X Sin. X lin. The focussing of the microscope could not now be 

 done by hand, as the distance from the ground glass was too great for 

 my arm, so I carried a long brass rod through wooden blocks under 

 the camera, and fitted a small grooved pulley wheel on it just under 

 the fine adjustment screw of the microscope, and put a milled 

 screw on the other end under the focussing screen of the camera. 

 A fine elastic band passed round the pulley wheel, and the fine 

 adjustment screw then enabled me to focus comfortably, with my 

 head under the black cloth, by turning the milled screw already 

 mentioned. As the microscopic objective had to be brought very 

 considerably closer to the object in order to throw a sharp image 

 on the focussing screen than when focussed with the eyepiece in 

 the microscope alone, I noted from experiment the amount of this 

 variation by measurement, and screwed down the coarse adjust- 

 ment of the microscope the necessary amount before connecting it 

 with the camera, and, in this way, left only the final focussing to be 

 done with the apparatus described above. 



This answered much better and gave me many very excellent 

 results, but I was still not satisfied, as I found that, unless the ova I 

 wanted to take were small or had a comparatively fiat upper surface, 

 only a portion of the resulting picture came out sharp, and all the rest 



