ILLUSTRATIONS. 
PLATES. 
Page. 
Plate I. Method of covering small tree with bell or hoop tent 16 
II. Fig. 1.— Brick furnace, tank, and derrick used in the tannin treat- 
ment for mildew, San Bernardino County, Cal. Fig. 2. — Machine 
for covering trees with sheet tents 20 
III. Fig. 1. — Method of attaching tent to hoisting pole by a half hitch of 
the rope. Fig. 2.— Top of derrick, showing method of attaching 
pulley. Fig. 3.— Base of derrick, showing method of construct- 
ing braces 22 
IV. Fig. 1. — Supply cart used with the improved system of fumigation. 
Fig. 2. — Supply wagon devised by C. E. McFadden, of Fullerton, 
Cal 22 
V. Figs. 1-5. — Successive stages in placing a tent over a tree with 
poles. Fig. 6. — A tented tree, showing method of securing the 
distance around the bottom of the tent by means of a tape at- 
tached to an iron rod 26 
VI. Removing the tent from one tree onto another by means of poles. . 26 
VII. Placing a sheet tent over a tree by means of derricks 28 
VIII. Fig. 1. — A row of tented trees, with cart at one end of row, ready to 
commence dosing. Fig. 2. — Dosing a tree 38 
IX. Dosage Schedule A, for high-grade sodium cyanid 88 
X. Dosage Schedule f-A, for high-grade sodium cyanid 88 
TEXT FIGURES. 
Fig. 1. Map showing principal localities in southern California where citrus 
fruits are produced 7 
2. Plan for construction of octagonal sheet tent, 50 feet across, showing 
lines used in constructing octagon 14 
3. Method of attaching hooks to tent when covering trees with aid of der- 
ricks 16 
4. Ends of hoisting poles used in placing tents over trees 20 
5. Earthenware acid jar with attachments for field use 23 
6. Carboy with handles attached to facilitate pouring the acid and carrying 
the carboy 26 
7. Outline of a sheet fumigation tent marked according to the Morrill 
method 29 
8. Man carrying tray and water bucket as practiced under the old system 
of fumigation 31 
9. Dosage schedule No. 1, for potassium cyanid 34 
10. Chart showing total amount of gas evolved when different proportions 
of water are used 45 
11. Dosage schedule No. f , for potassium cyanid 59 
12. A cover device attached to a fumigation generator 75 
13. -Laboratory apparatus used in the decomposition of cyanids and collec- 
tion of the liberated hydrocyanic-acid gas 100 
IX 
