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THE JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
drecipitate is formed. This is filtered o f f a n d washed with benzo’ t o remove t h e excess of aniline. T h e benzol is allowed t o evaporate spontaneously or in a Vacuum desiccator. T h e compound so obtained is a black powder unaltered b y exposure t o dry air a n d practically insoluble in water, b u t suffering a slight decomposition. DIMETHYLANILINE-Abenzol solution of dimethylaniline was treated with a freshly prepared solution of v a n a d i u m tetrachloride in benzol. A green precipitate or tar-like substance separated out on standing a n d adhered t o t h e sides of t h e vessel. By adding absolute ether t o t h e mixture, this separation was more complete as t h e compound appeared t o be insoluble in ether. By shaking the mixture, most of t h e substance could be made t o adhere t o t h e sides of t h e vessel a n d t h e main portion of the liquid poured off. After rinsing t h e product a couple of times with ether, it was dissolved in alcohol a n d transferred t o a beaker where t h e alcohol was allowed t o evaporate spontaneously in a warm place. PHENYLHYDRAZINE-it7hen a freshly prepared benzol solution of vanadium tetrachloride is added t o a solution of phenylhydrazine in benzol, a compound is formed. If t h e phenylhydrazine is in decided excess, t h e mixture is violet colored. B y t h e addition of more v a n a d i u m tetrachloride, it takes on a darker hue. T h e precipitate was filtered off using suction, a n d washed with benzol. TOLUIDINE-A solution of vanadium tetrachloride in carbon tetrachloride was treated with a solution of toluidine in t h e same solvent, a n d a black precipit a t e resembling t h e aniline compound mas obtained. This precipitate was filtered off, washed with benzol a n d dried in a v a c u u m desiccator. T h e analysis does not correspond with either of t h e formulae given in Table I, due, no doubt, t o t h e compounds, a s prepared, being insufficiently washed free f r o m excess of vanadium tetrachloride. T h e compound containing t h e higher percentage of chlorine a n d v a n a d i u m showed a marked tendency t o absorb moisture f r o m t h e air a n d become tar-like, also due, probably, t o a n excess of uncombined v a n a d i u m tetrachloride. ANMOXIA-A current of a m m o n i a gas was generated b y heating ammonium hydroxide a n d passing t h e evolved gas t h r o u g h a drying tower containing solid caustic potash. This gas was passed into a benzol solution of vanadium tetrachloride a n d a precipitate formed. When saturated with ammonia, t h e precipitate was filtered off a n d washed with benzol. I t was t h e n dried i n t h e air a n d analyzed. Portions I , z a n d 3 were m a d e a t different times. T h e compound is practically insoluble in water b u t decomposes on heating or on standing in water. hIinera1 acids decompose it with t h e formation of a bluish green solution. When heated alone in a closed t u b e , water is driven off a n d ammonium chloride sublimes a n d deposits on the cooler portions of t h e tube. T h e residue obtained after driving off all t h e volatile m a t t e r is black in color a n d earthy in appearance, a n d when analyzed was found t o contain 63.0 j per cent v a n a d i u m ,
Vol. 7 , No.
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showing i t t o be composed principally of vanadium tetroxide. B y continued heating in t h e air i t oxidizes t o t h e pentoxide. SIETHYLAMIXE--1ethylamine was prepared b y heating a 33 per cent solution a n d passing t h e evolved gas through a drying tower containing solid potassium hydroxide. T h e gas was bubbled through a filtered solution of vanadium tetrachloride in gasoline a n d a yellow precipitate formed. D I P H E & ’ Y L A M I S B - ~ ~ carbon tetrachloride solution of v a n a d i u m tetrachloride was a d d e d t o a n excess of a solution of diphenylamine in carbon tetrachloride. An indigo-blue precipitate was formed which, when dried, was grass-green. BENZOL--When vanadium tetrachloride is added t o benzol, t h e mixture has a slightly darker color t h a n vanadium tetrachloride alone. If t h e mixture is allowed t o stand some time, a precipitate settles out a n d hydrochloric acid is formed a t t h e same time. By pouring off the excess of benzol solution, filtering a n d washing with benzol, a purple colored compound is obtained which is unacted upon b y d r y air. By heating in a test tube, brownish vapors were given off. When a d d e d t o water, it dissolves, with hissing, forming a brown colored solution. T h e compound was analyzed b y dissolving in dilute nitric acid a n d proceeding in t h e manner previously described. Portion I was obtained after a mixture of benzol a n d v a n a dium tetrachloride had stood for a b o u t six weeks. Portions z a n d 3 were obtained b y allowing t h e action t o continue a shorter time. ANTHRACENE-( I ) When a solution of vanadium tetrachloride in carbon tetrachloride was mixed with a solution of anthracene in t h e same solvent, a black precipitate was immediately formed a n d hydrochloric acid given off. ( 2 ) Another portion was prepared b y mixing a carbon tetrachloride solution of v a n a d i u m tetrachloride with a solution of anthracene a n d heating under a reflux condenser for two hours. CHEMICAL L A B O R A T O R Y COLORADO SCHOOL OF MINES,GOLDEN
THE COMPOSITION OF FROZEN ORANGES AND LEMONS’ By H. D. Y O U N C ~
Received J u n e 21, 1915
There is very little information, so far as the-author has been able t o find with t h e limited library facilities a t his command, as t o t h e effect of freezing temperatures on t h e composition of citrus fruits. Whenever a freeze occurs in one of t h e citrus districts a n d t h e injured fruits begin t o appear on t h e market, t h e daily press contains dispatches as t o t h e findings of health officers in t h e larger cities, b u t very little, if a n y , records are t o be found in t h e scientific journals. Following a very severe freeze in January,’ 1913, in Southern California, a large amount of work was done 1 Paper No. 9, Citrus Experiment Station, College of Agriculture, University of California, Riverside, Califotnia. 2 Grateful acknowledgment is made t o Mr C. 0. S m i t h a n d Mr: E. E. T h o m a s , University of California, a n d Miss Alpha Rasor, W i n t h r o p College, Rock Hill, S o u t h Carolina, for their assistance.
.
Dec., 191 j
T H E J O L T R S A L O F I - V D C S T R I A L A;VD E N G I N E E R I N G C H E M I S T R Y
as t o t h e effect of freezing on the composition of t h e juice of oranges a n d lemons, which is here presented. Among t h e points investigated were t h e specific gravity of t h e juice a n d of t h e fruit a n d t h e analyses of fruit picked a t short intervals a n d of other samples from fruit picked a n d stored very shortly after t h e freeze occurred. T h e sugars were determined b y Bertrand's method, t h e acid b y titration, using phenolphthalein as a n indiDlTA
ON
i039
of oranges picked on January 13th 2nd kept in storage, t h e specific gravity of t h e different fruits being determined every four days. T h e average of t h e 20 unfrozen oranges was 0.876 on t h e d a t e of picking a n d this had increased b y February 27th t o 0.936. T h e frozen oranges h a d a n average of 0.8jo a t t h e date of picking (mhich was a week after t h e freeze), a n d b y February 3rd this h a d decreased t o -0.820, 0.820 being
FROZEN A N D UNFROZEN ORANGES A N D LEMONS TABLE 11-AVERAGE SPECIFIC GRAVITYO F
TABLE I-AVERAGE SPECIFIC GRAVITYOF FRUIT NAVEL ORAKGES EUREKA LEMONS
Date 1/14 18 22 26 30 2/ 3 7 11 15 19 23 27 3/ 3 11 (a)
JUICE
SAVEL ORANGES ECREKALEMONS Diverent picks@) Stored lots(n) Different picks(b) Stored lots(a) Different pickF(b) Stored lots(u) Different picks(b) Stored lots(a) Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen F r o z m Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen 1 053 1.060 1.060 0,876 0.850 0.890 0.860 0.890 0.860 1.053 0.876 0.850 1:044 1.042 1.052 0.834 1.042 1 052 1 042 1 ,048 11646 0,872 0.846 0,907 0.833 0.879 0.876 0,840 1 056 1.046 1.050 1.041 1 . 053 1 ,046 0.874 0.926 0.807 0.834 0.889 0.803 1.055 1.044 0.884 0.838 1.055 1.047 1.045 I . 040 1.044 I ,041 0.930 0.870 0 ,820 ... 0.887 ... 1.047 1.046 0,885 0.832 1.046 1.045 1.040 1.046 1.038 1 037 0.941 0.864 0.810 ... 0.869 ... 1,050 1.045 0.884 0.821 I ,043 1.046 1 040 ... 1.051 , . . 1.045 ... 0.953 , . . ... ... 0.894 0.812 1 ,045 1 045 r.045 1.050 0:ssl ... 1.056 ... 1:0i8 0,873 ... 0.959 ... 0.903 ... 1.048 ... 1.044 ... 0.966 ... . . ... 1.053 i:o44 1.050 0 914 ... 1.053 1.048 1:oir ... 1.042 1 038 0:880 ... 0.968 ... 0.873 ... 0 ,923 ... 1.051 1 :048 . . 1.042 1.038 1 ... ... 0.928 ... 01863 1 :056 1:042 .. ... ... ... ... ... 0.936 ... 0:bll 1 OS5 ... ... ... ... ... ... ,.. 1:0;4 .. . 0.936 ... 0: 862 . . . 0 869 . . . . . . ... 1:046 1:Ojl 1.045 1:049 i:Oio 1 646 1:040 0.866 ... 0.865 . . . Av. 1:052 ... F r u i t picked on January 13th ( b ) SuccessiL.e new lots picked on d a t e given.
:
:
:bin
:
:
:
.
TABLE ,111-PER CEST TOTAL SL-GARIN
JUICE TABLE IV-GRAMS OF SUGAR PER FRUIT NAVELORANGES EUREKA LEXOKS SAVEL ORANGES EVREKA LEMONS Different picks(b) Stored lots(a) Different picks(b) Stored lots(a) Different picks(b) Stored lots(a) Different picks(b) Stored lots(o) Date Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen 7.2 1,3 10.56 3.39 3.39 7.2 ... . . 1.3 ... 1/14 10.56 8.92 7186 2.85 2:47 2.64 3: i6 2.3 5.0 4.3 1.0 0.7 0.8 0:9 18 9.18 6 : 54 3 6 . 6.6 1.2 1.1 3.6 0.4 9.43 7.51 2.88 2.12 3.12 2.89 ,. 9 3.4 0 5 22 8.87 7.08 2.94 2.47 4.9 1.2 9.39 7.44 2.07 2.41 I .3 3.2 0.8 0.3 2.2 0.4 7.28 26 8.07 6.4 3.8 1.0 0.2 3.67 2.95 1.3 0.3 i .50 6.38 2.83 2.33 6.2 2.9 8.32 7.29 5.8 2.3 0.2 2.71 1.60 0.9 8.09 6.99 3.14 2.5; 5.8 ... 1.0 0.1 2/,3P 9.11 7. 8 5 .. 2.77 7.9 6.3 2.3 0.8 . . 7.01 2.69 9.67 2.24 1.0 ... 0.08 .. 7.1; 9.00 2.96 2.54 7.6 3.1 8.8 2.0 ... ... 1.2 8.03 23 9,l7 0 08 2.1 10.11 2.79 2.57 2.11 ... ... 8.0 1.0 ... 0.2 1.2 8.82 .. ... .. 1.9 ... ... ... ... . . 3' 9:28 7.96 7.0 9.41 6:94 .. 3:30 2:21 8.5 1.9 ... ... 11 ... ... 0.9 0:08 2197 5.1 1:s ... ... 0.9 ... 15 8.42 8:63 9'03 i:44 2.79 2149 2:99 ?:46 ... ... ... I .42 ... , . . ... Average, 9 . 0 6 (a) F r u i t picked on JanGary 13th. (b) Successive new lots picked on d a t e given.
9
TABLE V-PER C E X T IKVERT SUGARIN JUICE TABLE VI-PER CEXT SUCROSE IK J U I C E N A V E LORAXGES EUREKA LEXOSS SAVEL ORANGES EUREKA LEMOXS Stored lots(a) Different picks(b) Stored lots(a) Different picks(b) Stored lots(a) Different picks(b) Stored lots(a) Different picks(b) D a t e Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen 1/14 4.69 4.69 .. 2.36 2.36 5.87 5.87 1.03 1.01 4.13 3.75 2.11 18 4.10 3'39 1.53 2.26 2:o3 5.0s 3:i5 4.79 4:ii 0.74 0:94 0.38 I 13 3 60 4.11 3.76 2.24 1.55 5.26 22 4.33 2.09 1.85 3.75 0 62 4.54 3.48 0.50 1.03 1.04 4.70 3.88 1.74 26 4.06 3.76 1.56 2.30 1.57 4.69 3.76 4.01 3.52 0.33 0.85 0.64 0.90 3.66 3.37 1.91 1.48 30 4.35 3.60 2.46 1.89 384 3.01 0.85 3.97 3.69 L o ? 1.21 1.06 2/]< , . 3.49 3.5i 2.26 2.09 1.98 1.30 4.51 .. 4.60 3.42 0.45 1.05 0.59 0.30 3.48 3.73 2.22 _. 2.35 1.73 4.51 4.37 3.28 0.43 .. 0.42 0.51 23 4.88 3:56 4.00 3.71 2.30 1.79 4.29 3161 5.00 4.32 .. 0.66 0.75 3 / .1 .. 4.77 3.85 2:25 1:42 1.99 1.50 5.34 4.97 n:54 .. 0.58 0.61 j:iS 3.35 .. .. 4:io 4161 .. , . 11 4:ii 3:45 .. 2:66 1;?4 513, 3149 .. n:64 0:47 15 4.87 3:95 2 : 42 3:5S 4'68 0 :5 5 Av., 4.62 3.60 4.12 3167 1.95 1.60 2'27 i:io 4 . 4 4 3 . 8 2 4190 3:i9 0.63 0184 0:72 0:;s (a) F r u i t picked on J a n u a r y 13th. ( b ) Successive new lots picked on d a t e given.
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,
TABLEVII-PER CEKT ACID IN JUICE TABLEVIII-GRA%S ACID PER FRUIT K A V E LORANGES EUREKA LEMOSS hTAVEL OR.\KGES ElJREK.4 L E M O S S Stored lots(a) Different picks(b) Stored lots(a) Different picks(b) Stored lots(a) Different picks(b) Stored l o t s ( i ) Different picks(b) Date Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen Unfrozen Frozen IJnfrozen Frozen 1/14 1.56 LS6 1.38 5.81 1.1 1.1 ... 2.3 ... 2.3 , , 18 1.56 1.60 1.45 4:i3 0.9 n:9 0.8 0.8 2.0 1,5 2.0 1.2 22 1.67 1.62 1.68 1'49 5.02 1.3 0.8 1.2 0.7 2.9 1 0 2.4 0.: 26 1.47 1.74 1.69 1.83 4 6; 0.9 0.5 1 3 0 8 2.9 0.7 ... O., 30 1.68 1.88 1.53 1.59 3.66 1.2 o,, 1.3 0.9 0.4 2' 3 0.4 2/ 7 1.68 , , 1.50 1.51 4,i2 1 1 .. 1.1 0.5 0.3 2.2 0.3 15 1.59 1.31 1.34 6.72 ,. 6.32 5.18 1.3 1.0 0.4 2.0 .., 2 3 0.2 23 1.40 1:29 1.22 1.37 5.64 4.72 1.2 0'6 1.2 0 3 ... ... 2 3 0.2 1.38 1.15 7:?6 5:i9 6.19 5.73 . .. .. 1.1 0.3 2.8 0.1 3.0 0 5 i:i9 i:i4 .. .. .. .. 0.9 0.3 ... . . ... ... 1.6 0.2 11 i:io i:21 ,. .. .5,23 ... ... 1.1 0.3 ... .. . ... . . 15 i:ii 1120 7.73 5:65 4.79 0 7 0.3 ,.. ... 2.4 ... ... .. Average, 1 . 4 9 1.35 1.45 1138 6.98 5:20 6.27 .. ... , . ... .. ... .. . . (a) F r u i t picked on J a n u a r y 13th. (b) Successive new lots picked on d a t e given.
;.?
3'5
cator a n d calculating t o anhydrous citric acid. I t may safely be assumed t h a t t h e frozen f r u i t had approximately t h e same composition at t h e t i m e of freezing as t h a t of t h e unfrozen fruit of t h e d a t e of J a n u a r y I 3 t h j as the differences which t a k e Place in a week's growth are slight in the case of oranges a n d lemons.. SPECIFIC G R A V I T I E S
T h e first two' columns in Table I present t h e record
t h e lowest range of our method, which consisted in submerging t h e fruit in alcohol of varying density until t h e fruit was in equilibrium with a liquid of known density. Columns 3 a n d 4 present t h e results of successive new lots of oranges picked every four days. The specific gravity of t h e sound oranges does not change appreciably, varying on both sides of 0.876. T h e frozen oranges on t h e tree decrease very rapidly,
I 040
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
however, f r o m 0.850 on January 13th t o -0.820 on January 30th. Stored lemons show t h e same kind of changes as oranges, b u t of a greater degree, since sound lemons increased from 0.890 on January 14th t o 0.968 on February I j t h , and t h e frozen lemons decreased from 0.860 t o -0.820 on J a n u a r y zzd. The fruit on t h e tree remained approximately t h e same if unfrozen, b u t decreased very rapidly in specific gravity if frozen. T h e explanation of t h e different behavior of sound a n d frozen fruit probably is as follows: Freezing kills t h e protoplasm of t h e cells in t h e fruit a n d so changes t h e cell wall from a living, semipermeable membrane t o a dead, porous mass similar t o a sponge. I n t h e frozen fruit, therefore, connection is established between t h e rind a n d t h e p u l p , ' a n d t h e water which is evaporated from t h e outside is replenished from t h e pulp without t h e fruit suffering much diminution of volume. Losing weight and retaining approximately its original volume, i t must, obviously, decrease in specific gravity. The unfrozen fruit, on t h e other h a n d , loses very little, if a n y , moisture, except from t h e rind, which shrinks down very markedly a n d so decreases t h e volume of t h e f r u i t : as t h e weight does not decrease proportionately, t h e specific gravity increases. The difference in t h e evaporation from t h e rind is shown very clearly b y t h e following example: two oranges were picked on January 13th a n d stored for two months; they were t h e same size, 3*/16inch in diameter on picking; when cut, t h e sound fruit h a d decreased t o z ~ inches, / ~ while t h e frozen fruit h a d lost only '/I6 in., measuring 3 inches. T h e fact t h a t t h e specific gravity of t h e juice of frozen fruit decreases, in spite of t h e large loss of moist u r e (as shown b y t h e amount of juice which could be extracted), would seem t o indicate t h a t a n actual destruction of t h e sugars a n d acids takes place (probably b y fermentation). SPECIFIC GRAVITY O F THE JUICE
Because of t h e large number of samples used, i t was not possible t o make determinations on all of t h e m each four days. T h e charts, therefore, present a rather irregular appearance. T h e specific gravity of t h e juice of unfrozen oranges in storage, Table 11, does not seem t o change appreciably, b u t i t remains consistently greater t h a n t h a t of frozen oranges. T h e juice of frozen oranges has a n average specific gravity of 1.046 throughout t h e greater p a r t of t h e experiment, increasing quite markedly toward its expiration. T h e juice of t h e sound oranges has a n average of I . o j Z which remains approximately constant. T h e oranges picked a t different intervals, Table 11, show about t h e same averages, except t h a t t h e frozen ones do not show a n y constant increase toward the end of t h e experiment. T h e averages for t h e different picks is 1.051 for t h e sound fruit a n d 1 . 0 4 j for t h e frozen, both figures being slightly less t h a n for t h e stored lots. T h e figures for t h e lemons show about t h e same thing; t h e juice of t h e sound fruit is heavier t h a n t h a t of t h e frozen. There are more irregularities in t h e tables for lemons, d u e t o t h e difficulty of getting a sample of
Vol. 7 , No.
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uniform ripeness. By January 3 0 t h ~ t h e frozen lemons in storage had dried out so completely t h a t i t was no longer possible t o get enough juice to determine t h e specific gravity. On January 30th, 20 lemons picked January 13th yielded a total of only 31 cc. of juice. TOTAL SUGAR
T h e work on sugar a n d acid is presented in t w o different ways: first, t h e per cent in t h e juice, a n d s e c o n d , t h e actual amount present in t h e juice of one fruit. While t h e latter figure is admittedly not exact because of t h e difficulty of extracting all the juice, yet, in view of t h e fact t h a t t h e approximately same size oranges were used in all cases, it permits of a basis of comparison t h a t is very striking. Studying first t h e percentage composition of t h e juice in regard t o t h e total sugar, Table 111,t h e sound oranges in storage show considgrable variation b u t in no definite direction. I t is apparently only t h e variation of sampling. The frozen oranges show, however, a slight b u t definite increase. T h e average of t h e sound lots is 9.06 per cent a n d of t h e frozen 7 . 4 2 per cent throughout t h e experiment. The average of t h e fruit picked a t different dates is 9.02 per cent for t h e good a n d 7.44 per cent, or (within t h e limits of error) t h e same as t h e average of t h e stored fruit. T h e percentage of sugar in t h e juice of lemons shows t h e same kind of variation as in t h e case of oranges, t h e average of t h e determinations for stored lots of unfrozen lemons being 2 . 8 per cent a n d of stored frozen lemons 2 . 5 per cent. T h e determinations on samples picked at intervals show a n average of 3 per cent for unfrozen lemons a n d 2 . 2 for frozen ones. T h e actual amount of sugar present, Table I V , shows much greater differences. T h e stored sound oranges show considerable fluctuation, b u t no definite change. T h e frozen oranges, however, show a very marked decrease in t h e amount of sugar present, dropping t o less t h a n z grams of sugar per fruit, against a n average for t h e sound ones of 6 . j grams. T h e fruit remaining on t h e tree showed almost t h e same differences, dropping t o t h e same point, t h e sound fruit showing a slightly greater average t h a n t h e stored fruit, or 6.9 grams. T h e lemons show again the same kind of variation as t h e oranges, b u t of different degree. The unfrozen stored lemons average 1.0 gram sugar per fruit, while t h e frozen ones decrease from 0.7 t o 9.2 grams per fruit. T h e different picks show about t h e same a m o u n t of variation. Tables V a n d VI, for invert sugar a n d sucrose, present d a t a t h a t are little different from those in t h e total sugar. I n other words, there seems t o be n o change in t h e relative amounts of t h e different classes of sugar present. ACID
T h e percentage of acid, Table V I I , in t h e frozen a n d a n d unfrozen oranges in storage decreased in almost t h e same degree. The average of both lots in storage was t h e same, 1.49 per cent. The fruit picked a t intervals show t h e same character of change, but have a slightly lower average, t h e sound oranges showing
T H E J 0 1. R S d L 0F I N D U S T RI A L A AV D E AVGI N E E RI N G C H E M I S T R Y
Dec., 1 9 1 j
1 . 4 j a n d t h e frozen 1.43 per cent. Turning t o t h e actual a m o u n t of acid present in a fruit, Table l ' I I I q a very marked difference is found. T h e frozen oranges shorn. a very small a m o u n t of acid present, 0.3 gram against a n average of a b o u t I g r a m for t h e sound oranges. Lemons have, of course. a much higher percentage of acid t h a n d o t h e oranges. T h e y also show a greater variation between t h e sound a n d frozen fruit t h a n t h e oranges do. T h e stored lemons which were unfrozen average 7.0 per cent acid throughout t h e experiment. r h i l e t h e frozen ones average j . 2 per cent. T h e fruit picked at different intervals averaged 6.3 per cent for nine samples of unfrozen lemons, a n d 4.6 for t h e same number of frozen samples. T h e comparison of t h e actual amounts of acid present in individual lemons shows t h e same striking differences between t h e frozen and unfrozen ones t h a t oranges do: t h e a m o u n t in t h e unfrozen lemons, showing considerable variation, ranges from 2 t o 3 grams: in t h e frozen fruit, however, i t practically disappears. S ULILI A R Y
I-The principal change caused in citrus fruits b y freezing is a n excessive loss of moisture. This is shown b y a marked lowering of specific gravity. 11-The percentages of sugar a n d acid decrease slightly b u t definitely. 111-Since t h e change in t h e composition of t h e juice is slight, its edible qualities are not impaired if i t is n o t frozen so severely as t o cause i t t o d r y up. SOUTHERN CALIFGRXIA PATHGLOCICAL LABGRATORY WHITTIER. CALIFORXIA
THE IMPORTANCE OF FINENESS OF SUBDIVISION TO THE UTILITY OF CRUSHED LIMESTONE AS A SOIL AMENDMENT By WALTERTHOMAS A N D WILLIAMFREAR Received June 25, 1915
After experiments at t h e Pennsylvania Experiment Station a n d elsewhere h a d demonstrated t h e value of calcium carbonate i n t h e form of pulverized limestone as a neutralizing agent for acid soils, m a n y questions were addressed t o t h e Station as t o t h e conditions necessary for its successful use, a n d particularly with regard t o t h e fineness t o which it should be reduced for economical results. This subject was much discussed b y t h e producers of crushed limestone who, naturally, were desirous of meeting t h e growing dem a n d for this product at t h e lowest manufacturing cost compatible with its fitness for use. Experiment Station writers differed in judgment as t o t h e importance of this quality. Agricultural literat u r e contained little t h a t bore directly upon t h e question. T h e work of Bernard' a n d Heinrich2 was n o t sufficiently broad in its scope t o afford a n answer t o a question of so great economic importance. The experiment of Voelcker3 a t Woburn was t o o indefinite t o a d d much t o our knowledge. I n none of these experiments, moreover, was t h e q u a n t i t y of limestone used proportional t o t h e acidity of t h e soil. 1
Le Calcaire.
3
Merge1 II. Mergeln, p. 29. Jour. R a y . Agric. SOC.England, 71 (1910). 349.
1041
T o afford a n answer t o t h e question, t w o series of experiments were planned in t h e early summer of 1911 b y Walter Thomas, B.S.,under t h e writer's direction, a n d conducted during t h e fall of t h a t year a n d succeeding months. The same lot of crushed limestone was used as t h e amendment in both series. T h e stone was obtained from t h e American Lime a n d Limestone Company, of Bellefonte, Pa., a n d was a good representatil-e sample of t h e compact blue stone from t h e Trenton beds of t h a t locality. T h e crushed stone was carefully sifted through sieves of 2 0 , 40, 60. 80 a n d I O O meshes t o t h e inch. T h e p a r t coarser t h a n I , ? O in. was rejected. T h e several lots of siftings t h u s obtained were separately analyzed t o ascertain if t h e y differed in composition. The fine siftings in this case contained 98.13 per cent. t h e coarser ( l , ? ~t o 1/40 in.) 95.93 per cent of calcium a n d magnesium carbonates. T h e intermediate lots increased constantly in carbonate richness i n their order from coarser t o finer. T h e average of t h e five analyses was : Acid insoluble 0 42
+
FesOs A1203 2 86
CaCOs 95.93
MgCOa Total 0 84 100 05 per cent
Kotwithstanding t h e slight differences in composition shown b y these lots of differing fineness, each was used in these experiments in quantities strictly proMgO) content. portional t o its (CaO
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SERIES I
T h e soil used for this series represented P l a t 3 2 , of t h e General Fertilizer Series of Experiments, which h a d , every t w o years since 1881, received dressings of dissolved bone-black, muriate of potash, a n d nitrogen in t h e form of sulfate of ammonia. Owing, doubtless, t o t h e influence of t h e last-named fertilizer ingredient, this soil h a d developed a highly acid condition, a n d produced low crop yields in consequence : its supply of fertilizer constituents was not deficient. T h e acidity of this soil, as used for this series of experiment, indicated a lime (CaO) requirem e n t (Veitch) of 3 . 2 0 0 Ibs. a n acre-7 inches. T h e culture experiments were made in small, paraffined wire-baskets, of sl/z X s 3 / 4 in. size, with medium red clover as t h e crop. T h e saturation capacity of t h e soil (water-free) was 19.0 per cent, a n d moisture t o two-thirds t h a t a m o u n t was supplied a t t h e beginning of t h e experiment a n d carefully renewed, as need was shown b y frequent periodic weighings during t h e course of t h e test. T h e weighed a n d moistened soil, previously well mixed with enough of t h e limestone t o meet its lime requirement, was filled into each pot with t h e usual precautions t o secure uniform compactness. Eighty clover seeds were sown i n each pot, b u t t h e number was thinned t o fifty after t h e plants were well established. E a c h lot of limestone was represented b y three pots identically treated. During t h e first six weeks of t h e experiment, t h e plants were kept out-of-doors, with cloth shelter for nights a n d rainy days. Owing t o t h e lateness of t h e season, growth was slow. On Nov. 3rd t h e plants were removed t o a greenhouse, with a temperature of 45-60' F. Thereafter t h e y grew quite well, though
