132. REPORT OF THE COMMISSIONER OF AGRICULTURE. 
the hydrocyanic acid gas. Whenthese two gases are reduced to theliquid state by 
pressure or by great cold, it is found that the liquid carbonic acid boils at 2a much 
lower temperature than the liquid hydrocyanic acid does. A given quantity of 
water will dissolve about its own volume of carbonic acid gas, but all of this gas 
thus may afterward be expelled by boiling. 
Remarks.—Of the three processes described above, it is evident that the dry gas 
process is preferable to either of the others. Not only is there less labor in its 
manipulation, but it is also much cheaper than either of the other processes; this 
will readily appear from the following estimates of the cost of the material neces- 
sary for treating an orange tree 20 feet tall and having a diameter of top of 14 feet: 
o 
Dry cyanide process. 
24 ounces potassium cyanide, at 5 cents per ounce....... aleve, Seyeis eins here $1.20 
52 fluid ounces sulphuric acid, at 178, cents per ounce ............... eee i oe Ot 
Rota Meier eileen’ eta tree ae Acts 3 ¢ apse a lois, 8 ajo al® © Sierpiehe a6: eh Fer 23 RBA 
Dry gas process. 
47 fluid ounces cyanide solution, at 24 cents per ounce.......... a9 ars ola saree 
26 fluid ounces sulphuric acid, at 13%; cents per OUNCE.......ceceeeeereereeee 282 
Cyanide and soda process. 
4% fluid ounces cyanide solution, at 24 cents per ounce .............0..2.00. $1. 20 
43 ounces bicarbonate of soda, at $ cent per ounce................-......2:- .21 
40 fluid ounces sulphuric acid, at 14% cents per ounce ................2-.00- - 49 
Robali e sae scot ee stoke tec PARAS DS ME Ee ieee ero Se ane mae Cee ae 1.90 
These prices are those current in Los Angeles when the various ingredients are 
purchased in small quantities at retail; when purchased in large quantities they 
could be obtained at a much lower rate. Mr. A. Scott Chapman, of San Gabriel, a 
member of the California State Board of Horticulture, informs me that he pur- 
chases the best grade of potassium cyanide in large quantities at the rate of 50 
cents per pound, and I have been shown a letter, addressed to Mr. J. W. Wolfskill, 
of this city, wherein a firm in Saint Louis, Mo., offered to furnish commercial sul- 
phuric acid of the best grade at the rate of 2 cents per pound, net; the freightage 
on this acid from Saint Louis to Los Angeles would amount to about 5 cents per 
pound, making a total cost of 7 cents per pound for the acid delivered at Los An- 
geles. At these prices the cost of treating an orange tree 20 feet tall and 14 feet in 
diameter, by the dry gas process, would amount to about $1, not reckoning in the 
labor and interest on money expended for the apparatus. 
After the tree has been confined in the gas the proper length of time the tent 
should be entirely removed from it. On two different occasions I simply opened 
the tent to aliow the gas to escape, after which the tent was again placed on the 
tree and the doorway of the tent left partiilly open ; itremained on one of the trees 
for seven consecutive days, while on the other tree it was allowed to remain only 
for a day and night, but in both instances the trees were nearly killed. 
The generator used in the production of the hydrocyanic gas is as shown in the 
foreground in Plate V; it was originally devised by Mr. Alexander Craw and my- 
self, and has given perfect satisfaction. 
This generator consists of two leaden vessels placed one above the other and con- 
nected by a brass stop-cock; to the end of the valve of this stop-cock is firmly soldered 
an [L-shaped piece of an iron rod, to be used in opening and closing the stop-cock. 
The lower vessel is entirely closed above; near one side of the top is a screw-cap, 
covering the opening through which the proper chemicals are to be introduced into 
the vessel, while on the opposite side is an opening over which is firmly soldered 
the end of aleaden pipe, through which the gas passes on its way from the generator 
to the tent. When it is intended to pass the gas through sulphuric acid this leaden 
pipe is made to enter one side of an upright leaden vessel, and as near the bottom 
of the vessel as possible; to the top of the leaden vessel is attached a tin or leaden pipe 
which conducts the dried gas into the tent. Of course, if it is not desired to pass 
