MECHANICS AND FSEFUL ARTS. 11 7 



appearance is visible, then it is tune to break up the pit and spread it on the 

 ground to dry. 



When the plant is dry, which will be in from five to ten days, the woody 

 portion is separated by passing the plants through any ordinary rollers or 

 bearers, or by horses treading on them. By this process I get the fibre from 

 the wood, and have all its strength and elasticity preserved, and am now able 

 to manage it without having such great quantities to handle. Several of the 

 fibres of the finest qualities will be perfectly prepared by this process for 

 manufacturing. The coarser fibres can be water-rotted for a few days, say six 

 to eight, when they can be fitted for market or manufacturing by the common 

 process of breaking, scutching and hackling flax or hemp. 



PLASTER CASTS OF LEAVES AND FLOWERS. 



The following process is recommended by an eminent English engraver, for 

 obtaining accurate and beautiful casts from the leaves and other parts of 

 plants. The leaf, as early as convenient after being gathered, is to be laid on 

 a fine-grained, moist sand, hi a perfectly natural position, with that surface 

 uppermost which is to form the cast, and being banked up by sand in order 

 that it may be perfectly supported. It is then, by means of a broad camel- 

 hair brush, to be covered over with a thin coating of wax and burgundy 

 pitch, rendered fluid by heat. The leaf is now to be removed from the sand 

 and dipped in cold water; the wax becomes hard, and likewise tough, to 

 allow the leaf to be ripped off without altering its form. This being done, 

 the wax mould is placed in moist sand, and banked up as the leaf itself was 

 previously ; it is then covered with plaster of Paris, made thin, due care being 

 taken that the plaster be nicely pressed in all the interstices of the mould; by 

 means of a camel hair brush. As soon as the plaster has jKt, the warmth 

 thus produced softens the wax, which, hi consequence of the moisture of the 

 plaster, is prevented from adhering to it, and, with a little dexterity, it may 

 be rolled up. parting completely from the cast, without injuring it in the 

 least. Casts obtained in the manner thus described are very perfect, pos- 

 sessing a high relief, and form excellent models, either for the draughtsman 

 or for the moulder for architectural ornaments. 



MARINER'S TIME COMPASS. 



This new instrument, invented by Mr. Reeder, of Cincinnati, consists of a 

 chronometer, and a horizontal dial, with a style on its face, and a stationary 

 equatorial brass ring laid out hi degrees, minutes, and seconds. These are 

 supported on a movable axis, forming the focus of a vertical quadrant laid out 

 in angles at each side, so that the angle of dial and ring can be changed by a 

 thumb screw. Below the dial is the common mariner's compass, with a 

 spirit-level on its table or standard top. The instrument is designed to be 

 used with the compass in steering ships, and its object is to indicate the 

 position of the ship at any hour of the day when the sun shines, thus ope- 

 rating as a corrector of the compass, which is liable to be affected by local 

 attraction in iron ships, and by masses of metal, such as a cargo of wrought 

 or pig iron . 



