SCIENTIFIC NOTES. 255 



hardened in the moulds, are broken up into large pieces. These fragments 

 are deposited in iron vats, which are then filled with water. The water 

 dissolves a certain portion of the carbonate of soda which is contained in 

 the black ash ; and, when the water becomes sufficiently impregnated with 

 the dissolved carbonate of soda, the liquor is drawn out of the iron vats 

 into receivers, and from thence it is pumped into pans, in which it under- 

 goes the process of boiling, until, by evaporation, the liquor becomes of a 

 certain specific gravity or strength. 



It is then run into another furnace, called a white ash furnace, into 

 which it is boiled down or roasted into a solid, called white ash or caustic 

 soda, which is a carbonate of soda still in an impure state. In this condi- 

 tion or degree of refinement it is generally sold by the manufacturer, and 

 used by soap manufacturers ; but it is capable of a still higher degree of 

 refinement, when it becomes the carbonate of soda used in medicine, and 

 sold by the chemists. 



irirattfit Uto. 



Skeleton Leaves. — A good method of obtaining these beautiful dissected 

 leaves is frequently asked for. The following is a process which we can 

 recommend from experience. Steep the leaves, seed vessels, or other parts 

 of the plant, which are required to be dissected, in rain water ; leave them 

 exposed to its influence until the whole of the soft or pulpy matters are 

 decomposed. The period required for this operation varies much in 

 different leaves, &c, according to their texture ; thus, some require but a 

 few weeks, others as many months. When the pulpy parts are completely 

 decomposed, the next operation consists in their removal from the fibro- 

 vascular network with which they were originally connected. This requires 

 much care and patience. There are two ways of accomplishing it : one, 

 which consists in carefully exposing them to a stream of fresh water, using 

 at the same time a brush ; and the other, by simply placing them in fresh 

 water and removing with care the decomposed portion, in like manner, with 

 a brush. Some difficulty will be found at first in doing this without, at the 

 same time, breaking the fibro-vascular net- work ; but a little practice will 

 soon render it easy of accomplishment. The adoption successively of 

 simply fresh water, and a stream of the same, applied by means of a syringe, 

 will be frequently found desirable. The pulpy portions having been 

 removed, and the fibro-vascular network obtained, the latter must then be 

 bleached. For this purpose prepare a weak solution of chloride of lime, 

 by adding about an ounce of a strong solution of that substance to a quart 

 of distilled water ; then soak the skeletons in this solution for some hours ; 

 generally three or four will suffice, but when they are very thick a longer 



