September, 1912. 



KNOWLEDGE. 



345 



beads (see Figure 3751 ; 2, separate 

 elongated beads (see Figure 376) : 

 3, exclamation or clubbed markings 

 (see Figure 377) ; and 4, cuneate or 

 wedge-shaped markings (see Figure 

 378). 



The scales of T. donwstica appear 

 to contain a highly-refractive oil\ 

 substance in their composition, .uul 

 when they are heated and subjected 

 to mechanical pressure air-bubbles 

 may be observed to move along the 

 tubes. Some successful attempts wen- 

 made to produce the structures of the 

 scale on a large plan by crossint; 

 tubes of glass (filled with lii|uidsl al 

 %'arious angles. .-Vs a result of thesL- 

 experiments a model, with two 

 revolving sets of tubes in contact, 

 was made, with which, by obliciue 

 illumination, cuneate markings were 

 readily produced and photographed 

 (see Figure 379). 



James Strachan. 



Cuneate markings produced b 

 illumination of a model 



A NEW MICRO-TELESCOPE.— 

 To all those who possess microscopes the knowledge that 

 their instruments may be readily converted into telescopes 

 of high power at small cost will be 

 extremely interesting. The principle of 

 this new invention, which is due to Mr. 

 A. Cornell, of Tonbridge. Kent, resides 

 in the combination with an ordinary 

 mounted microscope of a telescopic 

 objective and the " pin-hole." This 

 combination produces an extremely sharp 

 inverted image in the plane of the micro- 

 scope stage, the inversion being corrected 

 by the microscope element of the 

 combination. 



The attachment for converting a 

 microscope into the telescope shown at 

 Figures 380 and 381 consists of a draw- 

 tube a carrying a suitable objective 

 and containing a series of diaphragms 

 for stopping down the light. These 

 diaphragms are so proportioned that 

 the amount of light is maintained through 

 acute angles by concentration ; as, for 

 instance, when using an object glass of 

 seven-inch focal length. These graduated diaphragms 

 provide for extremely sharp definition, .\lthough the focal 

 angle is extreme, the flatness of 

 field and the wide angle of same 

 are extraordinary. With a telescopic 

 objective of seven-inch focal length 

 and a micro-objective of one-inch 

 focal length a magnification of forty- 

 five diameters is obtained. With 

 such an arrangement Jupiter and 

 four of his moons were observed 

 with astonishing clearness during 

 June. The best general results were, 

 however, obtained with a one and a 

 half inch micro-objective, which so 

 far has given the brightest and most 

 clearly defined image. With this ob- 

 jective the magnification was about 

 twenty-seven diameters. 



The attachment is made to fit into 

 the diaphragm or Abbe illuminator 

 rim or under-fitting d on the stage 



or sub-stage. By means of this combination when the teles- 

 cope attachment is in place any degree of magnification from 

 twenty to forty-eight diameters maybe obtained by adjustment 

 of the draw-tube and eyepiece to focus the micro-objective. 



The only alteration to the micro- 

 scope which is necessary is to remove 

 the stop screw or bar so as to allow 

 the eyepiece to be lowered below the 

 horizontal to admit of observing 

 objects at an elevation. The ordinary 

 reflector c may be removed, or simply 

 turned out of the line of the tube of 

 the attachment a. Vov astronomical 

 purjrases and to facilitate observation 

 at high angles, such as the moon or 

 -tars at or near the zenith a reflector 

 /) is attached to the tube a. This 

 iitlector is ground optically correct 

 for the purpose and is mounted upon 

 a universal joint so as to be adjustable 

 in all directions. By means of this 

 I ertector objects overhead or at high 

 iiiglcs may be observed with the 

 greatest ease and comfort. When 

 the micro-telescope is employed for 

 terrestrial observation, a tube c is 

 employed to screen light from 

 the gap between the stage and 

 the micro-objective. This tube fits 

 on to the micro-objective nioimt 

 and is readily attached or removed. 



The combination forms an exceedingly compact telescope of 

 about fifteen inches in length, and the 

 mechanical adjustments are available 

 for focusing. To further facilitate 

 observation, however, the tripod stand 

 is secured to a special rotatable base 

 mounted on a pedestal or tripod, the 

 rotatable base being movable by 

 means of suitable screw adjustments 

 about vertical and horizontal axes, or 

 two axes perpendicular to each other 

 but inclined to the vcitical or horizontal. 

 Provision is thus made for keeping an 

 object in the field of the telescope when 

 it is being employed for astronomical 

 purposes. 



obliijue 



Figure 380. 

 The Micro-Telescope 



Figure 381. 

 The Micro-Telescope used horizontally. 



K O "i' A L MICROSCOPICAL 

 SOCIETY.— June 19th, 1912. H. G. 

 Plimmer, Esq., F.R.S., President, in the 

 Chair. — A paper by Lord Avebury was 

 read, giving a short account of the 

 development of pollen and of recent 



researches on fertilization which shows more and more 



complexity. He divided pollen into : — 



(1) Aerial pollen carried by the 



wind. This was probably 

 the original form, and was 

 dry, spherical and smooth 



(2) .Aerial pollen carried by insects, 

 which as a rule was elliptical, 

 but often spherical, in which 

 case it was generally spiny. 



(3) Sub-aqueous pollen, often 

 elongated and filiform. 



The forms of pollen are very various 

 — barrel-shaped, square, facetted, 

 dumb-bell shaped and many abnormal 

 and peculiar types. He then alluded 

 to the distribution of these forms in 

 the different orders ; in some of which 

 the pollen is more or less uniform, 

 while in others there are differences 

 even in the same species. 

 The general colour of pollen is yellow, but it is sometimes 

 orange, violet, blue, purple or white. 



Perhaps the most remarkable case is that of the loosestrife 

 (Lythruin salicaria) in which the pollen of the short stamens 



