iS° 



HARD WICKE 'S SCIENCE - G OSS IP. 



the ammonia until it has caused a complete diffusion 

 of the red stains within the objects : this it will do in 

 a few seconds. Now transfer the objects to another 

 small vessel or watch-glass containing pure water 

 alone, and wash and press them with the camel-hair 

 pencil. It will be well to change the water a few 

 times during the washing. The ammonia will now 

 be partially cleaned off, but yet the diffused red stains 

 will remain within the objects, and must be removed. 

 To do so, place the objects in a drop of water on a 

 glass slide, cover with a thin glass, and use a tapping 

 pressure with a needle. The reddish fluid will pass out 

 of the objects, and they will become quite clear. Retain 

 a steady and easy pressure with a wire spring clip, and 

 put the slide into a cup of water, and move it fre- 

 quently with an alternate dipping and draining action, 

 to wash away the expressed fluid and every trace of 

 ammonia. The objects may then, whilst still under 

 pressure, be allowed to become dry, gradually, in the 

 usual way, to prevent any too sudden or too great 

 contraction, and, if subsequently treated with turpen- 

 tine, they may be finally mounted in balsam. 



I have now in view, under a good quarter-inch 

 object-glass, a slide containing seven such lips, 

 prepared a year ago, and on most of them the teeth 

 can be seen with a clearness of definition and a 

 precision of outline that leaves nothing to be desired ; 

 and I feel no inclination whatever to attempt any 

 further experiments at improvement by mounting in 

 either gum damar or glycerine : I am quite satisfied 

 with the old-fashioned Canada balsam, and the 

 beauty of the results of the process I have described. 



HOW TO MAKE AN HERBARIUM. 



( Continued. ) 



By John W. Buck, B.Sc. 



IN speaking of laying out the specimens, I omitted 

 to give one hint which may be of service : I refer 

 to the judicious use of the scissors. It will sometimes 

 be found advantageous to cut away leaves and 

 blossoms, from what we may call the back of the 

 plant, when there are too many of them, and when 

 they would conceal one another's shape by their 

 number. It has the effect also in many cases of 

 making the specimen look more natural, since, when 

 growing, the branches of a bushy plant do not in- 

 commode one another, but spread out equally on all 

 sides. A bunch of berries — those of the spurge laurel, 

 for example— must generally be partly cut away. 

 Sometimes it is well to postpone the operation until 

 the specimen is dry and ready for mounting. But 

 be very cautious that in cutting you do not disfigure 

 the plant, or deprive it of some important feature. 

 Every plant has its characteristic kind of inflorescence, 

 or flower-arrangement, and also of leaf-arrangement, 

 and if you snip away recklessly you will produce 



effects that will sadly puzzle any botanist who may 

 afterwards look over your collection. 



The pressure necessary for the thorough preserva- 

 tion of the plants may be caused by large books laid 

 over the papers, with a few bricks on the top, or by 

 strapping the papers together between two strong 

 boards. The latter plan I prefer, and almost always 

 make use of, because the whole affair can be carried 

 about from place to place if required, or set before, a 

 fire to diy quicker, which is often a great convenience. 

 I need hardly say that, however the plants are pressed, 

 they should always be in as diy a place as possible. 

 As regards the amount of pressure to be applied, it 

 should be borne in mind that the object is not to 

 squash the plants but to keep them flat and dry them ; 

 and hence, especially with succulents, a too excessive 

 pressure should be avoided. If, however, enough 

 paper be interposed and the specimens well distri- 

 buted among the sheets, ordinary plants will take no 

 harm under any reasonable pressure. 



In transferring the plants, when changing the sheets 

 of porous paper, it will be found advantageous not to 

 lift up each plant by itself and place it on another 

 sheet, but to adopt the following plan. After having 

 lifted away the damp sheets above the plant — which 

 must be done with great care, by turning them slowly 

 back with the right hand while guiding and modera- 

 ting the operation with the left, which should be held 

 down on the upper surface of the paper you are 

 removing, — place a diy sheet over the plant. Then 

 take up the two uppermost sheets, with the plant 

 between them, carefully invert them, lay them on the 

 pile of dry sheets, and lastly skin off the clamp sheet 

 in the same way as before. Even by this method it 

 will not be found easy to keep the blossoms and 

 leaves of some plants smooth, as they are so apt to 

 stick to the papers. All blossoms that are at all 

 troublesome had better be dried separately ; and in 

 the case of such as poppies, they should be protected 

 by a couple of pieces of tissue-paper, which should 

 not be removed until the drying process is quite over. 

 The chief difficulty in transference will be found only 

 while the plants are damp, and will disappear entirely 

 as they get drier. The damp sheets should be com- 

 pletely dried before using them again, by exposing 

 them to warm, dry air. 



There are several ways of judging when the plants 

 are dry. In the first place, a thoroughly dry plant is 

 generally rigid, unless it be very long and weak. 

 Feeling of the plant by the lips, or placing the hand 

 on the sheet of paper from which it has just been 

 taken, are other tests, but in these cases you must 

 distinguish between coldness and dampness. Gene- 

 rally speaking, you may rest satisfied that if the 

 specimen has been under pressure, with dry and 

 frequently-changed papers, for eighteen or twenty 

 days, it is likely to be quite dry, unless its nature is 

 such as to make the matter doubtful. 



Now comes the mounting, which should not be 



