HARDWICKE'S SCIENCE-GOSSIP. 



m 



Of the former we have au example in the tooth 

 of Cladodus (fig. 113) : tliis is a sharp couical tooth 

 covered with shallow striations ; whilst of the 

 latter the teeth of Orochis (fig. 114) and Psammodus 

 are instances. The former presents a serrated edge, 

 whilst the latter is perfectly smooth. 



Such are the characters of some of the fishes 

 which formerly roamed in the carboniferous seas. 

 Though but little is at present known of them, that 

 little is sufiicient to fill us with admiration of the 

 wisdom and power of Him who has created all 

 things. Rev. W. H. Painter. 



HOW TO CUT VEGETABLE SECTIONS. 



By Waltek White. 



" "XTT"-^ want pretty and interesting objects." 

 ' ' This is the cry, which waxes louder in 

 proportion as our ranks are augmented by the 

 enlistment of fresh recruits. Let me commend to 

 their notice sections of stems, leaves, seeds, and 

 other portions of plants. They are pretty, as well 

 as interesting ; easy to mount, and moreover, when 

 well mounted, very permanent. How to cut them 

 is the rub. This seems to be a great stumbling- 

 block; consequently we find very few amateurs' 

 cabinets containing a really good selection of vege- 

 table sections. One will tell you he hasn't time to 

 cut them ; another, that he has tried and failed ; 



proverbial conquerors, of all difficulties, — namely, 

 patience and perseverance. Assuming the reader 

 to possess the two latter, I will proceed to put him 

 in the way to possess the former. 



I first began to think of cutting sections on 

 September 1st, 1866, from seeing on that day, in 

 Science- Gossip, a description of an instrument 

 which I, in my innocence, then thought would 

 answer that purpose. How anxiously I tried shop 

 after shop before I could find the one where I could 

 invest my penny in a music-binder ! I need scarcely 

 say the affair was a failure. Some time afterwards 

 I got a watchmaker to cut me a screw, with which, 

 a fishing-rod ferule, and a bit of brass plate, 1 

 knocked up an uncouth-looking piece of apparatus, 

 which served my purpose pretty well for a long 

 time. Yet, as the screw was not so fine or so well 

 fitted as I could have liked, I cast about for a 

 friend to cut and fit me a better. After many in- 

 quiries, I came into contact with a gentleman who 

 very kindly recommended me to try wedges instead 

 of the long-sought micrometer-screw. I took my 

 nondescript to pieces, and in a very short time con- 

 verted it into a machine, which, for truthfulness, 

 simplicity of manners, and withal lightness of figure 

 (in the cost thereof), leaves little or nothing to be 

 desired. Here is an outline sketch of the appa- 

 ratus, fig. 115 ; here also is the receipt for making 

 it. Take a brass tube (fishing-rod ferule), T, about 







1 



of an inch diam., and 



Ih in, 



long; inside of this 



Fig. 115. Diagram of Section cutting Machine. Scale i. 



while a third has heard so much of the diflaculty of 

 section-cutting from those who have attempted it, 

 that he thought it useless to go to the expense of a 

 machine. Now, I hold that everybody who takes 

 up the study of Microscopy ought early to learn 

 how to make a good microscopic section. In His- 

 tology this acquisition is indispensable. As a 

 means of mastering the art, nothing can be better 

 practice than" operating on the subjects before- 

 mentioned. There is no royal road to section- 

 cutting, any more than there is to other branches 

 of Microscopy; yet a few practical hints may 

 smooth the path a little, and tempt a few to turn 

 some of their leisure moments in that direction. 



The first thing necessary is a section-machine ; 

 the second, a sharp-cutting instrument. Besides 



tube fit a brass plug (P) of the same length. When 

 smeared with tallow, this should fit the tube with a 

 water-tight joint. Solder one end of the tube (T) 

 into a hole that will just receive it, in the centre of 

 a brass plate (X) 3 in. x 1| in., 

 and about ^-in. in thickness, 

 having a hole at each corner to 

 pin or screw it down' to the 

 block (B). This is the metallic 

 portion, which any country 

 tinker can easily make. The 

 wooden portion can just as 

 easily be made by any coun- 

 try carpenter — W, W, two 

 wedges, each 15 in. long, i in. thick, and 1 in. deep 

 at the base of angle. They should be worked up 



Fig. 116. 

 Section of ditto. 



these, two other things are also needed— those two true out of a thoroughly sound piece of beech or 



