1894.] MICROSCOPICAL JOURNAL. 23 



which he is working, and on which the microscope is 

 pLaced, may have his hands on the stage of the latter 

 where the object is which he is examining, whilst he 

 looks into the eye-piece to see what he is doing while 

 dissecting the object; which amounts to saying that the 

 proportions which have appeared to me most suitable are 

 those where the stage is raised about a decimetre (4 in.) 

 above the table, and the entire tube of the microscope is 

 only about 2 dm. (8 in.) long or a little more. The diffi- 

 culty of arranging and suitably fixing the object which 

 one examines being equally one of the greatest incon- 

 veniences in this kind of research, especially in the case 

 of very small objects which a displacement of 1-10 mm. 

 will cause to travel out of the field of the microscope, 

 and which one ordinarily thus loses without being able 

 to find them again, this inconvenience requires that such 

 objects should be capable of being turned on themselves 

 in every direction without displacing them from their 

 situation in order to attack them from ail sides. This 

 advantage I have obtained by simply making the stage 

 of the microscope movable on its centre. By this means, 

 without touching the object itself, whether it be fixed or 

 not, one can place it in all desired positions, and that 

 without its receiving the slightest shock which might 

 displace it. The observer requiring to have his hands 

 firmly resting on this same stage while dissecting the 

 object which he is studying, I have also found that the 

 most suitable width for such a stage is that where it has 

 about 1 dm. (4 in.) in breadth." 



He goes on to state the requirements of such a micro- 

 scope in a similar way at some length, but enough has 

 been quoted to suggest that we meet here for the first 

 time with a precise definition of what has become the 

 standard dimensions of the Continental microscope 

 stand. 



Up to 1835, which appears to have been about the date 



