152 Transactions of the 



Under the continued action of the concentrating heat of the 

 condenser the oil becomes much more fluid. The spherules look 

 brilliant, and at one focus of a brilliant sapphire hue, at another a 

 dull ruby red. The Tolles' glass gave an appearance of fine bead- 

 like convexity — 14-inch tube and C eye-piece. 



In a paper * in the ' Monthly Microscopical Journal,' Jan. 

 1870, I related the phenomenon of fluid shooting between the 

 ribs of the Podura, and almost obliterating a row of beads by the 

 insinuation of the water through the cracked cover. I was pleased 

 some time since to find that, subsequently, Mr. Joseph Beck ex- 

 hibited at the meetings a somewhat similar appearance, caused 

 by ingeniously breathing upon a scale ; the fluid was seen to run 

 along the grooves caused by the ribs. 



I have always described the Podura as ribbed and beaded. Of 

 course a string of minute beads approximately forms a rib. I am 

 inclined to believe the beads or ultimate molecules fill up the corru- 

 gations really forming beaded ribs ; and I deduce this fact from the 

 black edgings frequently seen in the interrupted ribs optically 

 forcing the so-called spines. 



to refer to former beliefs. Speaking of the Podura markings, in July, 18G9, a 

 great student in Podura and otlier test objects wrote, p. 26 : — 



" Under this excessive amplitude each individual marking retains its charac- 

 teristic form . . . not the most careful focussing can determine that it stands 

 above the surface of the scale." 



" Under the parabolic condenser, with a ith object-glass and a black field, 

 this is a most beautiful object.'' 



"In all other respects of interval, form, and position they are the same as 

 under transmitted light, and we are equally unable to prove that they exist in 

 the form of projections." 



" By transferring the investigation to a scale tliat has been ripped open or 

 torn across, nothing can be learnt. The tear continues without interruption clean 

 through the markings, one half of which will be left on one piece and one half 

 on the detached one, and no snags or projections can be seen on the clear edges 

 of the suture." 



Comparing this with recent statements, there is reason to believe that 

 definition is now greatly improving. 



* Page 13. ... " the beads look just like rows of peas in a pod. But the 

 water is now insinuating itself, and bright spots four times the size of the beads 

 arise like blebs of a bright green colour. One rouleau vanished instantly." " I 

 had the satisfaction of exhibiting several times to Mr. Eeade the upper and lower 

 beads of the test-scales he brought with him." (Kev. J. B. Keade, President.) 



