114 SUMMARY OF CURRENT RESEARCHES RELATING TO 



by its means to prepare by himself a new series of twenty preparations 

 at pleasure. The hitherto general practice of laying the object to be 

 inspected on large glass slides, and fastening over them the thin, 

 round or square, cover-glasses, presented so many difficulties that a 

 preparation seldom succeeded well, especially if it were put up for 

 any length of time. 



With each of my new revolver Microscopes is given a second stage- 

 drum, with twenty empty apertures, and a sufficient number of small 

 round glasses and spring-rings for firmly fixing the preparations. 

 The stage-drum with the preparations already attached to the Micro- 

 scope is unscrewed from the milled disk, and the second empty drum 

 put in its place. 



The insertion of a new object is so exceedingly simple, that direc- 

 tions for it seem, properly speaking, superfluous. In the first place 

 a small round glass is washed clean, and with the forceps belonging 

 to the Microscope, is laid in one of the apertures, then the object to 

 be examined is laid in the middle of this glass, either dry or with 

 mounting liquid (glycerine, gelatine, Canada balsam, or in cases where 

 only a rapid observation of an object is required, even water, spirit, 

 &c.), and covered with a second previously cleaned glass, fastened down 

 with a spring-ring which goes into a small groove made for it, and 

 the preparation is ready. (!) It must, however, be here observed 

 that all hard objects (especially insects) must, in order to succeed well, 

 be previously heated for a few seconds in a small reagent glass, with 

 caustic potash over a spirit flame, by which means the preparations 

 become soft and quite transparent. 



The preparations are perfectly protected from dust by a pasteboard 

 cover, and care must be taken always to replace the cover over the 

 stage-drum, after using the Microscope. If, in spite of this, dust 

 should after a time fall upon the preparations, it must be carefully 

 brushed away from both sides by the soft hair brush accompanying 

 each Microscope; any other cleaning of the preparations is never 

 necessary. 



If desired these Microscopes can be supplied with special objects 

 previously given me to prepare, and for the requirements of schools 

 the stage-drum can be fitted with botanical, zoological, or minera- 

 logical preparations. Price according to agreement. 



This entirely new, and in every respect original and practical 

 Microscope offers to every one such a fund of entertaining and in- 

 structive matter, and will prove to the teacher as well as the student 

 such an inexhaustible source of suggestive occupation, by which to 

 pass the leisure hours usefully and pleasantly, that there is scarcely 

 anything better fitted for a present, always gladly seen, especially by 

 the ripening student. The price is fixed as low as possible, and con- 

 sidering the prices ruling here may be called very cheap." 



Herr Schieck intended, we have no doubt, to be strictly accurate 

 when he announced his instrument as " entirely new " (ganz neu) and 

 " in every respect original." But it was in fact anticipated by two 

 now in Mr. Crisp's collection, which were made more than fifty years 

 ago, by T. Winter (simple) and Harris and Son (compound, fig. 11). 



