not deliberately rejected. n'hen such packages are sampled a tryer tapering toward the tip ought t o be preferred, if an ideal sample is aimed a t . lTnder the circumstances indicated, when
a cylindrical core is takcn, the sample will only be accurate if a sufficient number of corcs arc drairn in various directions and equably distributed. LEAD, S. DAKOTA, December 4 , 1911 I
LABORATORY PREPARATION O F LITMUS PAPER. Experience has shon-n that JT-ith a good quality of litmus papcr, uneducated workmen arc able to distinguish slight differences in shade, and maintain very slight acidities or alkalinities, if such arc desired. It is found, hon-ever, t h a t they are often decei\-ed by the quality of the litmus paper, which, through varying amounts of salts in the paper, may require widely differing amounts of acid or alkali to give a definite color. Practically all directions for the laborator)- preparation of litmus paper start ivith commercial litmus and require from Io pcr ccnt. to 33 per cent. solutions to make a sufficiently colored paper. Various methods of purifying this commercial product bpfore its use ilia>-be found in the literature, all of which require considerable time for sedimentation, and, usually, quite a n amount of alcohol, which makcs purification expensive. X great many have used a water extract of commercial litmus without further purification, neutralizing to meet their requirements. This gives a paper which is satisfactory for some purposes, but the red paper is usually rather impervious to \rater, and the large amounts of soluble salts Ivhich it contains cause reactions in the paper \i-hich arc often deceiving. These \-arious difficulties havc: led to the use of the chemically pure litmus xhich is sold b>- the various supply houses and can bc prepared iri about one-quarter of the time required by the ordinary substance. Although the chemicall>- pure litmus is listed a t ten times thc value of the commercial product, its coloring strength is so much greater that the final cost is never more, and in some cases is less. Continued trials have shon-n the follo\ving to be a \-cry satisfactory grade of litmus paper for all purposes, i1-hether laboratory or manufacturing, and the product \rill be found more delicate than most litmus papers o n the market. For blue paper, I . q pcr cent. of chemically pure litmus is dissolved in clistilled 1T-atc.r ivith constant shaking for about one hour. This solution is set aside over night, carefully decanted from thc small amount of sedirncnt, and sulfuric acid added. drup by drop, sufficient to reduce alkalinity to such a point t h a t a piecc of filter paper floated on the top and thcn dried
will assume a \-cry perceptible red color :aftcr being suspended 2000 h?-drochloric acid. one-half minute in To make red litmus paper a I .o per ccnt. solution of cheniically pure litmus is required Tvith thc addition of sulfuric acid until such a degree of acidity is reached t h a t a very perceptible reaction Jvill take place when paper floated and dried as before is suspended one-half minute in N / p o o caustic soda solution. Time of exposure to these standardizing solutions is round to be as important a function as the degrce of acidity or alkalinity of the paper. The above-mentioned degrees of sensitiveness arc closc to the practical limits, for if the papers are made more delicate they cease to bc red and blue. hut becomc lilac or neutral. The filter paper used is any smooth compact qualitative paper sold by the chemical supply houses. The bcst manner to saturate the paper Ti-ith litmus has been found to cut i t in strips about seven inches wide and to tlran the paper over the surface of the litmus solution, Trhich hns previously been placed in an ordinary shallow square-cornered cnamcletl bread-baking pan. Thc paper is held I)>- the ends and first touched t o the surfacc of the liquid, about t l r o inchcs €roil1 one e n d ; then the other end is released and the paper d r a n n don-n across the cdgc of the pan. Surface tension holds thc paper to the liquid, yet only one side of the paper is alloired to touch the solution, and drawing across the side of the pan takes aim!- an?- excess. Thc strips arc hung up to dry by pinning the blank ends over lines qtretchetl in some con\-enic.nt place. The paper \rill be lound very unifortii. as just sufficient solution will have bccn takcn up to dye all the sheets of the sainc shade. Onc liter of solution \rill make one hundred shcets seven inches b y tn-enty inches in sizc. These sheets may be rolled u p or packed airay in proper containers to protect them from the air. nntl cut in strips of eon\-enicnt size for use shortly before they arc neeilctl. I I X c mouthed. glass-stoppered bottles are found very conveiiicut for holding the small strips for daily use. Great uniformity is secured by making up large batches a t a time, and thc method a l l o w for closest similarity of succeeding batchcs.
E.
n-. I i I C r i .
PERILLA OIL. Product from the seed of Pt-rilla ocivzoidi,r (Nat. Ortl. Lal)iateae), an indigenous plant of India, China :ant1 Japan. Perilla oil is very similar to t h a t of iinseetl. In Manchuria, i t is uscd for edible purposes. The Japanese use the oil lor \vatcrproofiiig paper umbrellas. and lor preparing transparent paper for i v i i i do\rs. I n the colder portions of Japan. the plant is groi\-n a s LL fie1,l crop. The annual production oi d is about ~ o o . o o ohushel\. A bushel of seed gives up a galrim oi oil, .ii-orth ;o c m t s 1)er gallon. U. S.Consul Samnion, 1701;ohatn:i, Japan. in 1910 sugges,tetl the introduction of this plant intu the United States. Folloi\-ing this suggestion. a small quantity of the seed \vas iinported from Japan. During the season of I ~ I , I thii plant \vas gro\\-n a t ilkron, Ohio. Seed \rere sonm April 15th: 1)lants came u p 10 days later; growth slo\v; h1ooi;letl .\ug. j ' to Sept. l i t ; harvested Oct. Ist, after plants had Iwm injured l>>- l ~ - m t . Plant resists light frosts, b u t cannot resiyt drought. On the dry, sandy soil of n'est -Ikron, thc plant dit1 not d o xcll. On the damp, claj-ey soil the growth iras much hetter. S-ield of seed based on very small arca is about loo pounrls per acre. The seed of this Ohio-gro\rn perilla \vas 20 per ccnt. lighter, per equal volume of seed than the parent s e d . The crop did not fill irell; about 80 per ccnt. of the seed pockcts
