194 REPORT OF THE DEPARTMENT OF BOTANY OF THE 
conclusion that the proper sieve for the purpose is one made of 
20 x 20 mesh steel- or iron-wire cloth, the wire being No. 34 on 
the Washburn & Moen gauge. (lf a brass- or copper-wire sieve 
is used it should be 20 x 20 mesh No. 33 wire on the Old English 
gauge.)®® Unfortunately, ready-made sieves of this kind are not 
readily obtainable. Also, it is difficult to get them made, because 
few hardware dealers carry in stock the proper kind of wire cloth. 
Accordingly, the Station had a quantity of the 20 x 20 mesh No. 34 
steel-wire cloth made to order and placed it in the hands of Dor- 
chester & Rose, Geneva, N. Y., who offered in for sale during 
1907. The original lot has been all sold, now, but Dorchester & 
Rose have had some more made on their own account and expect, 
hereafter, to keep it for sale at twenty cents per square foot, post- 
paid. . 
A foot-square piece of this wire cloth tacked over a light wooden 
frame twelve inches square by three inches deep makes a cheap, 
serviceable sieve jor sifting alfalfa seed (see Plate XVI). 
With such a sieve a man should be able to clean from three to 
seven bushels of seed per day. One-fourth to one-half pound of 
seed should be put into the sieve at a time and vigorously shaken 
during one-half minute. In order that the work may be uniformly 
thorough the operator should use a cup holding not over one-half 
pound thereby making it impossible to get too large a quantity at 
one time. A watch should be kept constantly in sight and no more 
than two batches of seed should be sifted in one minute. If the 
seed is known to contain but little dodder, one sifting will do; but 
when there is much dodder and particularly if the dodder is one of 
the large-seeded kinds, two siftings, both made strictly in accord- 
ance with the above directions, are recommended. 
Our experiments and observations indicate that by the above 
method most alfalfa seed on the market in this State may be made 
practically free from dodder and safe to sow. Of course it is ad- 
*° No. 34 brass wire is not of the same size as No. 34 steel wire. In 1900 
the Wire Cloth Manufacturers’ Association adopted the Washburn and 
Moen gauge for all steel- and iron-wire cloth and the Old English gauge for 
all brass and copper-wire cloth. On the Washburn and Moen gauge No. 34 
wire has a diameter of .o104 inches. Hence, in 20x20 mesh No. 34 steel- 
wire cloth the actual size of the openings is .0396 in. each way. On the Old 
English gauge, No. 34 wire has a diameter of .0095 in. which makes the size 
of the openings in 20x20 mesh No. 34 brass-cloth .o4os5 in. each way. This 
is too large. No. 33 brass wire, which has a diameter of 0.1025 in. and 
gives openings .03975 in. wide, more nearly meets the standard requirements. 
