320 NOTES AND MEMORANDA. 



were replaced by young plants, occupying the same position, springing, 

 namely, from the fovea of the leaf. These were not the product of 

 the germination of the nmcrospores within their sporangium, the 

 macrosporangium being entirely suppressed. In their rudimentary 

 stage these non-sexually produced plants are simply conical emer- 

 gences, altogether resembling the rudiments of sporangia, but they 

 gradually develop into plants with ordinary leaves. These shoots 

 are not analogous to the bulbils which characterize many classes of 

 vascular cryptogams, such as Lycopodiacese and Ferns, in which the 

 Isoetese appear to be exceptionally entirely deficient, a phenomenon 

 closely connected with the absence of branching. It is rather an 

 instance of " apogamy " carried out to its most complete stage, namely, 

 the complete suppression, not only of the sexual organs, but of the 

 entire sexual generation. 



MICEOSCOPY, &c. 



Microscopes with Swinging Tailpiece. — This addition to the 

 Microscope has been revived within the last few years, and its novelty 

 having been the subject of some discussion, we have referred to the 

 provisional specification (not further proceeded with) of Mr. Thomas 

 Grubb, at the office of the Commissioners of Patents, in July, 1854. 

 The nature of the invention was thereby declared to " consist in the 

 addition of a graduated sectoral arc to Microscopes concentric to the 

 plane of the object ' in situ,' on which either a prism or other suitable 

 illuminator is made to slide, thereby producing every kind of illu- 

 mination required for microscopic examination, and also the means 

 of registering or applying any definite angle of illumination at 

 pleasure." 



On 1st August, 1876, letters patent were granted to Mr. John 

 Stuart (on behalf of Mr. Zentmayer, of Philadelphia) for improve- 

 ments in Microscopes by means of which the sub-stage carrying the 

 illuminating apparatus and accessories (together with the mirror if 

 desired) and also the object stage may be placed at any required 

 angle in relation to the optical axis of the Microscope and object- 

 glass, and also at an angle in relation to each other for the purpose of 

 more conveniently illuminating and viewing the object under exami- 

 nation, more particularly when oblique illumination is required. 



The iavention consists of a method by means of which the stem 

 which carries the sub-stage and the mirror may be made to swing 

 sideways to the right or left, either below or above the stage on a 

 centre having for its axis of rotation a line in the plane of the object 

 on the stage intersected by the optical axis, that is, a line passing 

 through the centre of the body and the object-glass of the Microscope. 

 The stage is also made to turn independently on a separate pivot, 

 having for its axis of rotation the aforesaid line. 



The figure represents in sectional elevation a portion of the 

 Microscope. 



S is the limb carrying the body with coarse and fine adjustments. 

 A is the stem which carries the sub-stage B, and mirror if required. 

 A is attached to S by the sleeve or socket I, clamped by the nut J, 



