1126 
Journal of Agricultural Research 
Vol. V, No. 34 
the needle is tempered, 1 then ground to a sharp point with a good stone, 
after which it is smoothed and polished with emery dust, crocus cloth, 
and rouge, and finally held carefully on a buffing wheel. The finished 
needle should be sufficiently smooth and sharp to enter and pass through 
a piece of ordinary writing paper without sticking or friction. In other 
words, this new needle must have as sharp a point and smooth a surface 
as any sewing needle. The important thing is to have the taper straight, 
beginning X inch from the end, and the needle above the taper exactly 
0.04 inch in diameter. 
1 The tempering solution consisted of 5 teacupfuls of common salt, 6 ounces of saltpeter, 12 teaspoonfuls 
of powdered alum, and 1 teaspoonful of corrosive sublimate dissolved in 10 gallons of water. The needle 
was tempered by heating carefully to a dull white heat and plunging at once into the tempering solution. 
It was then lightly cleaned with smooth emery cloth, heated carefully to a point below dull redness, and 
again plunged into the solution. 
