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HARDWICKE'S SCIENCE-GOSSIP. 



[Oct. 1, 1866. 



opening being covered with a dark cloth,. to prevent 

 light entering). I also nail another dark cloth on 

 the top of the box, and allow it to fall over my 

 head and shoulders ; this should be large enough to 

 enable one to use one or both hands to adjust the 

 stage, without the annoyance of having each time 

 to uncover the head. This is all I find necessary ; 

 and now, placing the microscope horizontal, and 

 putting on the tube so as to throw down a circle of 

 light when the object is illuminated, the image will be 

 seen beautifully defiued on a sheet of paper placed in 

 front of the draughtsman, who, instead of having to 

 bend over the end of the microscope, can sit at ease, 

 and with every comfort trace the outline and all de- 

 tails correctly without difficulty. When it is wished 

 to make a coloured drawing, it is well first to trace 

 it, and then, shifting the paper on one side, colour 

 it to correspond with the image which then will be 

 reflected by the side of the tracing. It is difficult 

 to be certain of the colouring being right, either in 

 tint or shade, when put over or on the reflection. In 

 daylight I have made drawings of diatoms by this 

 plan on a large scale, obtaining much clearer defini- 

 tion of the markings than I can do by the old 

 method. The prism I have now was made for me 

 by Mr. Baker, of Holborn, and is not expensive. 

 Any carpenter can make the box — or almost any- 

 thing will answer the purpose. The great advantage 

 is that both hands are free, and to make an accurate 

 coloured drawing is quite an easy occupation for 

 any one who can use pencil and brush. I have used 

 the camera in this form for many years, and have 

 often wondered that it has never been generally 

 used. When direct sunlight is obtainable, I use 

 powers as high as \ inch, and have found my § give 

 good pictures with the light of a belmontine lamp. 

 High powers are not necessary, as the size of the 

 reflection can be increased at will by raising the 

 microscope farther from the paper.— Geo, W. Hart. 



Cups for Maceration.— I have found it very 

 convenient in preparing objects for the microscope 

 to use a set of shallow saucers, which are to be 

 obtained of any artist's colourman. The set I have 

 consists of a little series of saucers of common 

 white ware ; the upper surface of each is hollowed 

 out in the shape of a watch-glass, and the under 

 surface to form a lid to the one below, and fits 

 tolerably closely on it. In these, objects can be 

 macerated for some days in any fluid which is not 

 excessively volatile, without drying up ; and the 

 whole set of six does not occupy more space than a 

 large watch-glass.— J. II. McK. 



Dry Mounting.— -At the last meeting of the 

 Quckett Microscopical Club, Mr. Burgess read an 

 interesting and amusing paper on this subject, which 

 he illustrates profusely by examples. The chief 

 feature in his process is the adoption of large pieces 



of glass, varying from an inch to three inches and 

 upwards in one direction, whilst three inches is the 

 " standard " for the other direction. By this means 

 a larger surface is obtained for mounting specimens 

 whole for low powers. The glass employed is thin 

 crown of -^ of an inch in thickness ; and the object 

 is placed between two plates of uniform size, with 

 a thin " mount," such as employed for photographic 

 portraits, surrounding the object, and interposed 

 between the plates, so as to constitute a large 

 shallow cell. 



Removing Dried Cuticles.— I shall be glad 

 to learn of the best method of separating the epi- 

 dermis of dried leaves from the rest of the tissue. 

 All the books on the Microscope refer to the sepa- 

 ration of the epiderm from freshly-gathered leaves ; 

 but they omit all notice of performing the same 

 operation on the already dried plant. Having re- 

 cently carefully examined my Herbarium, with a 

 view to provide materials for microscopic slides, and 

 having already over 1,000 forms of vegetable hairs, 

 I am anxious to elicit the best and readiest means 

 of separating these hairs from the leaves, in order 

 that they may be mounted in balsam for the polari- 

 scope. Some of these hairs are of exquisite beauty, 

 and many of their forms I have never seen figured. 

 — Charles Bailey, 



The Stanhopescope.— I am obliged to your cor- 

 respondent Mr. Bockett for his candid, though some- 

 what severe criticism of the Stanhopescope. The 

 instrument, as I stated, is of Erench manufacture, 

 and very cheap; it was scarcely to be expected, 

 therefore, that each lens would be equally well 

 adjusted so far as regards optical qualifications, and 

 such is the case. About one-half of those that have 

 passed through my hands were very excellent in- 

 deed, and although not free from either spherical 

 or chromatic aberration, were, nevertheless, suffi- 

 ciently flat in the field and prismatic to be of great 

 service to a searcher for either marine or fresh- 

 water diatomaceas. I have had applications for 

 about twenty-four dozens, and for the first few 

 days I sent stanhopescopes off without special exami- 

 nation, expecting that all were sufficiently good for 

 use ; but on close examination, I noticed that about 

 one-sixth were not correctly focussed, and those I 

 returned at once to the dealer. Possibly one of 

 the inferior specimens has fallen to the lot of Mr. 

 Bockett. I anticipate that all those I despatched 

 during the month of August and the latter part of 

 July gave satisfaction to those who received them. 

 I have written to a London optician, asking him to 

 manufacture a lens on the stanhopescope principle, 

 but with more careful attention to optical details, 

 and he informs me that such an instrument could 

 not be made for less than five shillings.— T. P. 

 Barkas. 



