144 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Fig. 28. 



This part of the apparatus is provided with proper clamps and set-screws, 

 so that motion is possible in the three dimensions of space, allowing 



perfect orientation of the 

 specimen. 



Mr. Kingsley has used 

 this machine for about three 

 months almost daily, and it 

 has proved itself all that 

 could be expected. It is 

 well-made and simple, and 

 it is an easy matter to cut 

 with it ribbons three feet 

 or more in length, without 

 a break and without losing 

 a single section, 



A second view of the 

 instrument is shown in 

 fig. 28. 



Plate Modelling Method 

 or Plastic Reconstruction 

 of the Object.*— Prof. G. 

 Born once again attacks 

 this subject in an article of 

 twenty-three pages. At the 

 end he apologizes for the 

 length of his article, but 

 bids his readers be of good courage, for the actual manipulation is not 

 nearly so long as the description. 



The method, which has been several times noticed in this Journal, 

 essentially consists in making an enlarged model of the object, from 

 which the sections are taken. The first principles are that no section 

 should be lost, that they should be of the same thickness, and that they 

 should be so marked that when laid together no difficulty should be ex- 

 perienced in applying them one to the other, or in cutting off or out the 

 superfluous parts. 



The object is as a rule imbedded in paraffin, and a block thereof made 

 so that the sides are parallel and the angles right angles. Certain 

 marks are intercalated on the block so that their correct position is easily 

 noted. When the sections are cut, the next thing is to draw a magnified 

 image of the object. This is done on sheets of wax, or rather a layer of 

 wax on a sheet of paper. The magnified image is then cut out of the 

 wax-paper, and all the sections having been laid together, an enlarged 

 model of the original object is produced correct in all its details. 



This of course sounds very simple, but the difficulty of manipulation 

 is great but not insurmountable. After having imbedded the object very 

 carefully in paraffin, it is laid in its rough state on the orthostat, an 

 instrument shown in fig. 29, O, F. The adjacent part of the apparatus 

 a 6 is then applied, and the outer space filled up with paraffin, so that a 

 roughly rectangular block is produced. But in order to make the sides 

 perfectly flat and level and at right angles, another instrument is 

 reqiaired. This is shown in fig. 30, the uplifted arm being a knife and 



Zeitschr. f. Wiss. Mikr., v. (1888) pp. 433-55 (4 figs.). 



