PRODUCTION- OF TULIP BULBS. 39 
never become cheap, because their production cost is relatively high. 
A comparison of the varieties in Plates XVIII and XIX, and an 
examination of the following performance tables (Tables 5, 6, and 7) 
will give valuable information on this point. It will be seen that 
between some varieties there is a difference in yield of 75 per cent 
or more. This is due to no accident or fault of location, but to the 
inherent characteristics of varieties. One is asked why Proserpine 
should be so expensive when it is an old, established variety. A 
glance at Plate XVIII, Figures 1 and 2, and its performance record 
will show that it is a poor reproducer and consequently the bulbs can 
never be cheap. Compare this with Artus (PL IV, Figs. 1 and 2) 
and Rosalind (PL IV, Figs. 3 and 4). In the autumn of 1919 these 
three varieties were planted at Bellingham, Wash., liberally, 14 to 
the row, mostly 8-centimeter round bulbs, but those of Proserpine 
averaged larger than the other two. Proserpine blossomed and 
made first-size bulbs with an increase of one or two, ranging from 4 
to 9 centimeters each, while Rosalind also produced a first-size 
bulb for next year but gave three to six increase, ranging from 
flowering size downward. 
The character of the reproduction is also a very potent factor 
of the cost. Some varieties produce a moderate number of large- 
sized bulbs as increase and others a large number of small ones. 
(Compare PL XX with PL V, Figs. 3 and 4.) 
The popular Keizerkroon (PL XVIII, Figs. 3 and 4) is not by any 
means the easiest to grow and can never become cheap, like Artus 
for example. 
PERFORMANCE RECORDS. 
The number of bulbs sold from a given area of ground in any one 
year is not necessarily a measure of the grower's success in bulb 
culture. Many factors and conditions are to be considered, among 
which are the sizes planted, the sizes marketed, and the nature and 
quantity of the increase. The factor which should be studied most 
closely is the nature of the increase, commonly termed "propaga- 
tion." (Compare PL III with Pis. IV and V and PL XVIII with 
Pis. XIX and XX.) After the merchantable stocks have been 
removed, there must be enough left of such sizes as will insure a 
similar product the following year to produce unqualified success. 
In Tables 5 to 7 the results of many measurements of many varie- 
ties, made in many ways, are given in sufficient detail to enable the 
grower to judge of the success of the experimental production here 
outlined. 
PROPAGATION BY ROWS. 
A satisfactory unit of measurement in tulip-bulb production is not 
so easy to get as might be thought. One unit, and possibly as good 
a one as any, is a row across the 3-foot bed. Since this row is stand- 
