4 BULLETIN 1250, U. S. DEPARTMENT OF AGRICULTURE. 
copper reduction methods were used,’ except in 1920, when sucrose 
was estimated by polarization before and after inversion. Because 
of the small quantity of starch in the seeds, a new method was 
employed.* 
Methods of judging maturity—The degree of maturity may be 
judged approxnatey. either by external appearance or by the com- 
position of the edible portion. When the work was begun external 
appearance, the only method then available, was used as a basis 
upon which to develop the second method. 
For the preliminary work, therefore, the melons were classified 
according to color, netting, and ‘‘slip.” ‘‘Slip” denotes the ap- 
pearance of the stem end after the else has been pulled from the 
vine. A “full-slip” melon is one that separates cleanly from the 
vine, no part of the stem remaining attached to the melon. If 
approximately half of the stem cavity retains its part of the stem, 
the melon is called a “‘half slip.” In this bulletin the term “field 
ripe’ is applied to a melon that becomes yellow on all or part of its 
surface while still on the vine. Melons that had grown fairly large 
but whose netting was so poorly developed as to indicate that they 
were plainly immature were classed as such. 
At best this is only a rough classification and can not be used to 
indicate small changes. As the work progressed it became possible 
to apply other and more accurate standards of maturity, based on 
the results of chemical examination, such as the soluble solids of the 
juice, its refractive index, the percentage of sucrose which it con- 
tained, or the starch content of the seeds. 
DISCUSSION OF RESULTS. 
CHEMICAL COMPOSITION AS AN INDICATION OF MATURITY. 
SOLUBLE SOLIDS IN JUICE. 
Table 2 gives the -percentage of soluble solids in the juice of 
melons at different stages of development. 
The juice of green melons had a lower content of solids than that 
of more mature melons. The difference between the full-slip and the 
half-slp melons appeared at first to be small. The 1917 results at 
Brawley probably may be depended on to decide this point, since 
they are based on the analyses of about 250 melons, the samples 
being continuous throughout the season. The difference between 
the average percentages is only 0.5. By applying mathematical 
methods for use in such cases, this difference exceeds its probable 
error five times, giving an assurance of more than 1,000 to 1 that 
full-shp melons have a higher solids content than half-slip melons. 
The failure of these data to show a more striking relation between 
the solids of the juice and the stage of development is due to the 
failure of the slip of the melon to show accurately small differences in 
maturity. The alt alas eroup contains many melons of good quality 
and full maturity, and the half slips in Table 2 probably included a 
large proportion of such melons. 
® Association of Official Agricultural Chemists, Official Methods of Analysis, 1916, pp. 87, 97, 109. 
‘ Journal of the Association of Official Agricultural Chemists (1922), 6: 175-191. 
