On a Netv Micro-telescope. 73 



some translucent substance which shall mark this spot and not be 

 in the way of observation. 



A thin transparent bristle out of a new tooth-brush I have found 

 to answer the purpose very satisfactorily. Selecting one of the 

 finest and straightest, cut a fine notch across the rmg in the direc- 

 tion of left to right, and placing the hair in the notch with its 

 inner end a little short of the centre, fasten it down at the other 

 extremity with a small piece of gummed paper, and when dry place 

 it in the eye-piece on the stop and replace the eye-lens as at first. 

 Its accuracy may now be tested by rotating the eye-piece in its 

 place, when the end will describe a very minute circle, in the centre 

 of which is the real centre of the field. 



My own pointer is movable. A small milled head is so cut that 

 it turns through only about one-sixth of a circle, and hence at one 

 extremity it brings the haii* across the field, and at the other it 

 carries it under the stop to the side so as to be quite out of view 

 when not in use. 



As regards the plan of notation, this -will probably have been 

 anticipated from the foregoing remarks ; for if a dot be sufiicient to 

 indicate the centre of the field, it will answer equally well to indicate 

 the relative position of any object in that field, and a dot in any 

 part of a square will serve to note down the precise whereabouts in 

 that square of any object of which it may be desired to preserve a 

 record. Thus, any particular specimen being found, substitute the 

 Maltwood and write down the two numbers contained in that square 

 over which the end of the jJointer rests, and make a dot in the same 

 relative position to the figures, as ^j-, or if it fall on the line, ??1 



mark the line as well either vertically or horizontally, but in all 

 other cases the hnes may be altogether ignored. The want of some 

 simple and easy, yet certain method of recording, has always been a 

 desideratum, but I find this plan leaves little more to be desired. 



IX. — On a New Micro-telescope. By Prof. E. H, Ward. 



This is designed especially for travelling and field use, but appli- 

 cable to some of the daily work of the microscopist. It consists 

 of a stand and accessories as follows : An ordinary tank micro- 

 scope having the body focussed by a rack and clamped at any 

 desired height upon a stand like that of the bull's-eye condensers. 

 Probably few naturalists have any suspicion of the real usefulness of 

 this little piece of apparatus, not only in the study of objects living 

 in an aquarium or preserved in alcohol, glycerine, &c., but for the 

 hasty inspection of herbarium specimens permanently fastened upon 



