160 REPORT OF THD BoTANIST OF THR 
The unions are brass with ground joints and those shown at u, 
Fig. 4, which allow of the shear motion of the arms, are fitted 
with set-screws to prevent unscrewing of the union. The hori- 
zontal lengths of pipe shown in Fig. 3, were cut approximately 
two feet long. The horizontal telescoping joints allow of closing 
the carrier for four-foot rows, or of extending it for seven-foot 
rows. The lengths of pipe which form the vertical supply pipe, 
shown in Fig. 3 and Fig. 4, also those which form the arms, were 
cut approximately 18 inches long. The telescoping of the arms 
combined with the shear motion is an essential feature in adjust- 
ing the nozzles for different heights and widths of rows. It is 
still an open question whether the vertical telescoping joints 
shown at j’ are of any real merit. One point is certain, the use 
of a telescoping joint in the vertical supply pipes which carry the 
arms necessitates extra fixtures and adds to the weight. The 
rods shown at r, Fig. 3, were provided to prevent twisting and 
slipping of the arms on the above joints, but as these proved 
more ornamental than useful for this purpose, an iron bar, shown 
at b, Fig. 4, was added. The latter prevents the twisting; it also 
strengthens the leverage for lifting the arms when turning . 
around; at the same time it prevents sliding of the vertical joints. 
By the use of the above bar, the rods shown at r, Fig. 3, are not 
essential. . 
At first the elbow put out with the “ Erin ” nozzle by the Gould 
Manufacturing Company, was used for attaching the nozzles. 
These proved to be too weak for practical use so were abandoned 
and eighth-inch ground brass unions substituted. By the use of 
a short piece of bent tubing these unions gave nearly as much 
freedom of direction as did the elbows. At the same time the 
unions would turn before breaking or wrenching off, but could 
be screwed tight enough to hold the weight of the nozzle. 
The size of tubing used in arms was one-eighth inch, telescop- 
ing into one-half inch, iron pipe sizes. The vertical supply pipes 
consisted of one-inch pipe telescoping over three-fourths inch 
pipe. The latter is not iron pipe size. The same dimensions _ 
