20 



SEEDS AND SEEDLINGS. 



get a cheap pair of apothecaries' scales (about 4s. ) and suspend them 

 from a ~| -shaped wooden frame fixed to a board below. If you get a 

 single gramme-weight and the fractions, you can make duplicate 

 gram me- weights from sheet- lead. 



The metric system of weights should be used. The unit of length 

 in this system is the metre, a platinum rod kept in Paris and originally 

 supposed to be a tenth-millionth part of the distance from the North 

 Pole to the Equator. The metre is multiplied and divided by 10 for 

 the higher and lower measures of length ; the Greek prefixes deca-, 

 hecto-, and kilo- represent 10, 100, arid 1000, and the Latin prefixes 

 deci-, centi-, and milli- represent '1, '01, and '001. The same prefixes 

 are used in the other measures. The unit of volume is the cubic deci- 

 metre, or litre, but the cubic centimetre (i.e. the millilitre), usually 

 written " c.c.," is often used for volumes less than a litre (1000 c.cs.). 

 The weight of 1 c.c. of distilled water at 4 C. is the unit of weight, 

 the gramme, with multiples and subdivisions as before. 



Place an inch-rule graduated to tenths or eighths and a centimetre- 

 rule graduated to millimetres edge to edge, and find how many centi- 

 metres are equal to a foot. If the scales are accurate, you should get 

 the number 30*5. 



Metric Equivalents (Approximate) 



1 inch = 2'5 centimetres. 



1 ounce (avoir. ) = 28 grammes. 



1 fluid ounce = 28 c.cs. 



1 centimetre = f inch. 

 1 gramme =15 grains. 

 100 c.cs. = 85 fluid ounces. 



Germination Jars. Into a large wide-mouthed glass jar put 



Fig. 12. Germination Jar. The seeds (Pea, Broad Bean, Sunflower) have had the 

 seed-coat and one Cotyledon removed. 



a rolled-up piece of blotting-paper, then fill up the jar with sawdust, 



