18 BULLETIN 3877, U. S. DEPARTMENT OF AGRICULTURE. 
The preparation finally proposed by Dr. Cross is made as follows: 
Prepare a sirup: 
Granulatedyoucar 962 a4 see see ae Es Pee ee pounds__ 15 
AWW a ber ses ate Ry dee ee ee SIE area pints2--447) 
Partinic acid: (crystallized. 22 22s 2 Nee ea ee _ounce_- 4 
Boil for 30 minutes. Allow to cool. 
Pussoive, sodium arsenite: (CO: be) ee ee eee ounce. #32 
Tn HOE Water 22 Se feel) Bee Te ae ae ae eee pint st 
Cool. Add poison solution to sirup and stir well. Add to the 
poisoned sirup: 
ET Ta Gy Sg a ee a ee pounds__ 1 
Mix thoroughly. 
Nie 
& : 
On April 23, 1914, Dr. Cross and the writer prepared two sirups of 
the above formula (exclusive of the honey, which only makes the 
sirup more palatable), except that one lacked the tartaric acid. After 
cooling, they were tested in a refractometer, with the following 
results: 
Sirup with tartaric acid, specific gravity 1.339, Brix (sugar content) 68.8. 
Sirup without tartartic acid (Nickels sirup), specific gravity 1.343, Brix 68.95. 
The Nickels sirup had lost 0.75 per cent of its sugar content and 
was of a very dark brown color. The new sirup was bright yellow 
(amber color), clear, and transparent. Equal samples of each were 
placed in quart exhibit jars with ground-glass stoppers, labeled, and 
set aside. A second reading was made on June 20, 1914, as follows: 
Sirup with tartaric acid, specific gravity 1.340, Brix 68.40. 
Nickels sirup, specific gravity 1.3321, Brix 67.01. 
The new sirup had lost 0.4 per cent of its total solids and had not 
noticeably changed in color or sweetness. The Nickels sirup had lost 
1.04 per cent of its total solids, was nearly black, partly crystallized, 
and had lost much of its sweetness. In the beginning of August the 
stoppers were removed and cheesecloth tied over the mouths of both 
jars, to find how evaporation would affect these sirups. The jars 
were placed on a shelf in the laboratory. In the beginning of 
January, five months after the jars were first left open, they were 
examined. Figure 2 shows the conditions. The difference in the 
quantity of the sirups, in color, and in the crystallization that had 
taken place within the jar containing the Nickels sirup may readily 
be noted. A reading was taken of these sirups, as follows: 
Sirup with tartaric acid, specific gravity 1.385, Brix 75.48. 
Nickels sirup, 1.367, Brix 72.68. 
1In the first experiments one-half ounce of tartaric acid was used, but this is found 
unnecessary. 
2In earlier experiments the sirup was boiled 30 minutes after addition of the poison, 
but boiling will raise the ** Brix’ (total solids), which is to the disadvantage of the sirup 
as an ant bait. 
