4 I2 
Thus, to dilute a solution from twenty per cent, 
to five per cent., add to each volume of solution 
20 
T 
- i 
= 3 of the diluting fluid. 
3. Approximate Values .— 
1 cubic centimetre = 17 minims. 1 minim = 
•059 c.c. 
100 cubic centimetres = 3 ounces, 4 drachms, 
20 minims. 
1 drachm = 3*55 c.c. 
1000 cubic centimetres = 1*76 pints. 1 fluid 
ounce = 28*4 c.c. 
4 litres = 7 pints. 1 pint = 568 c.c. 
1 gramme = I 5 fths grains (avoirdupois). 
1 grain (avoirdupois) — *0648 gramme. 
1 kilogramme = 2 pounds, 3 ounces, 119*8 
grains (avoirdupois). 1 drachm = 1*77 
grammes. 
5 kilogrammes == 11 pounds. 1 oz. = 28*35 
grammes. 
1 grain apothecaries’ — *0648 gramme. 
1 drachm apothecaries’ 5 = 3*88 grammes. 
1 ounce apothecaries’ 3 = 31*1 grammes. 
15*4 grains apothecaries’ = 1 gramme. 
4. 1 millimetre = *039 (a¥) inch. 1 inch = 2*5 
centimetres. 
1 centimetre = *39 (f) inch, xouo inch = '0253 
millimetre. 
1 metre = 3*28 feet, xio inch — f millimetre. 
xmo millimetre (V) = *00004 bich. 
5/* = soW inch, f p — 1o 60 0 0 inch. 
5 - Y = 3 * 59 - 
Circumference of a circle = 2 ttt = ird. 
Area of circle = 7rr 2 . 
