2 BULLETIN 1488, U. S. DEPARTMENT OF AGRICULTURE 
The following nine grades of upland cotton seven-eighth to 1 inch 
in length of staple grown east of the Mississippi River and similar lots 
grown west of the Mississippi were tested : 
Middling Fair No. 1 
Strict Good Middling No. 2 
Good Middling No. 3 
Strict Middling No. 4 
Middling No. 5 
Strict Low Middling No. 6 
Low Middling No. 7 
Strict Good Ordinary No. 8 
Good Ordinary No. 9 
The test lot of each of these grades of cotton consisted of a com- 
posite sample of approximately 250 pounds taken in equal portions 
from three different bales of that particular grade. The cotton for 
the spinning test was selected from bales which were being used in 
making up the types of working standards for grade. In order to 
reduce other variables, cotton was selected which was deemed to be 
as nearly as possible uniform in staple and character. The grade was 
certified by a committee authorized to class cotton under the pro- 
visions of the United States cotton futures act and of the United 
States cotton standards act. The grade of the cotton will be desig- 
nated by number throughout this report. 
MECHANICAL CONDITIONS 
To determine the comparative waste, these lots of cotton represent- 
ing each of the nine white grades were run under similar mechanical 
conditions, the drafts, speeds, and settings conforming to usual mill 
practice. The net weight of cotton taken from the bale was recorded, 
then the cotton was passed through the opener, and placed in a bin 
and allowed to condition for 24 hours, during which time it either 
gained or lost in weight, depending upon its character, the moisture 
in it, and the weather conditions. This gain or loss was reflected in 
the invisible waste from the pickers. 
After 24 hours the cotton was taken from the bin, weighed, and 
passed through the breaker and finisher pickers. The production 
and waste at these machines were weighed and recorded. As soon 
as convenient the production (called laps) from the pickers was 
transferred to the card room, weighed, and passed through the cards. 
The production and waste were again weighed. The cotton was then 
passed through two processes of drawing frames, three processes of 
roving frames, and then to the spinning department. Frequent 
weighings of the laps, slivers, and roving were made to ascertain 
whether proper size or weight was being delivered. 
MOISTURE CONDITIONS 
The relative humidity in the different rooms was kept as nearly 
constant as possible. It has been found from experiments that a 
relative humidity of 50 per cent in the picker room, 60 per cent in the 
card room, and 70 per cent in the spinning and weaving rooms gives 
satisfactory results. It is not alwaj^s possible to maintain precisely 
these moisture conditions, as the relative humidity is affected by the 
weather. Table 1 gives the averages of the hourly readings of the 
prevailing temperatures and relative humidities and the time required 
to pass each grade through each machine, Only in extreme weather 
