Lesson VIII.] 



TRY. 



110 



1 o, so as to make 

 it look like the black part 

 in the figure, then fold it 

 again upon itst-lf, until 

 it looks like the letter V ; 

 open it out, place it in a 

 uith dis- 



vater and pour the fig. 1*. 

 liquid gently into the filtering paper. If 

 the fluid docs not pass through readily, in 

 consequence of the paper adhering to the 

 sides of the funnel, place a straw between 

 iner and the funnel. 



What is digestion? 

 P. It is the process of obtaining the 

 soluble parts of sub- 

 stances by the aid of 

 heat A glass matrass 

 (Fig. 25) with a piece of 

 wire twisted round it to 

 suspend it over a spirit- 

 lamp, is used for the 

 purpose. When the va- 

 pour of the liquid in 

 which the substance is 

 digested is valuable, as 

 alcohol, the cork of the 

 flask is fitted with a long 

 open glass tube, so that the vapour be- 

 comes condensed in the tube and returns 

 again to the matrass, and on this account 

 :cesi is called circulation. 



100. T. What is decomposition ? 



I he separation of the component 



parts of substances, and may be (he result 



of the greater affinity of certain particles 



of the compound, for the decomposing 



lie caused by heat, elec- 



or galvanism, separating the par- 

 ticles. 



101. if precipitation ? 

 rowing down or separation of 



i the liquid whi^h 



holds it in solution, caused by some other 

 i.rcripitant is the body which pro- 



.d the pr 



thrown do*: usually 



-lasses like champagne 



* necessary sometimes 

 i>tincd 



:non fire, how i 

 procur 



P. By a very simple apparatus. Take 

 two common earthenware 

 flower-pots,without any flaw, 

 and twist some iron wire 

 tightly round the upper part 

 of each, then make three or 

 four holes (d), in the lower 

 part of one (a), and place it 

 on three or four stones so a.s 

 to raise it above the ground, 

 as in /'/'.-. IN. Have a piece 

 of sheet iron pierced with 

 holes r, fitted to this pot, 



and a chimney p, made of 

 8 |, eet j rou filted to tjie otner 



pot b, which should be somewhat larger 

 than the one just described. The chimney 

 should be about 2J to 3 feet long, and o 

 inches in diameter. When the heated 

 charcoal is placed above the perforated 

 sheet iron c, and the pot with the el; 

 covered over it, as in the Fig. abo\ 

 have an excellent temporary furnace. A 

 little practice with this furnace will soon 

 enable any one to regulate the quantity of 

 air required for the purpose of maintain- 

 ing combustion. Crucibles should be pur- 

 ci.a-.d. 



/Have we not another method 

 of obtaining an intense heat on a small 

 scale? 



Fig. 27. 



/>. Yes, by means of the blow-pipe. 

 me consists of an inner deoxidizing 

 or reducing flame d o, and an outer oxi- 

 dizing flame o. With a gns-jet ;uid blow- 

 pipe, or even a candle, and 

 tobacco-pipe, and charcoal, we 



may d. tain, or rcduro their 



metallic oxides to the metallic form. 



GENERAL QUESTIONS ON LESSON 



1. Can you describe to me the pro- 

 cesses of rcctific.r 



abstract!. >n ' 



hat are the weights made use of by 

 ittf 



