904 Brenchley . — The Development of the Grain of Barley. 
as possible. As with the wheat, and for the same reasons, the material 
contained in 1,000 grains was selected as the unit — a unit which will 
represent with the minimum of variation from period to period the material 
grown upon a unit area . 1 The several lots of 1,000 grains were counted 
out, weighed, dried in a steam oven for three days at too° C., then weighed 
again. Various determinations — ash, nitrogen, phosphoric acid — were made, 
and after being expressed as percentages of the dry weight of the grain the 
results were recalculated to give the actual amounts associated with 1,000 
grains in each case. The results obtained have been expressed graphically 
as curves, one for each property. In order to make a fair comparison 
between these curves the zero point was always reckoned as the day on 
which the first cutting was made, seven or eight days after flowering, so that 
^ rams 
Fig. i. Green and dry weights of 1,000 grains. Upper set of curves represent green weight, 
lower set dry weight. 
the grains at each period were of the same age, and had approximately 
reached the same stage of development. As barley is always allowed to 
become dead ripe in the field the fruiting period of the plant is an extended 
one, about fifty-six days elapsing between flowering and harvesting the ripe 
corn. 
Weight of Grain , Water Content , &c. Fig. i shows the actual green 
and dry weights of each sample of 1,000 grains. In the two earlier plots 
(A and B) the green weight rises for twenty-seven days and then falls 
steadily. The later P 2 0 5 -starved plot (C) reaches its maximum green 
weight six days earlier, and then shows a similar but rather accentuated 
fall. The dry weight rises steadily for twenty-seven to thirty-six days, then 
1 Brenchley and Hall ? loc. cit. , pp. 197-8. 
