A J D E S G I A- E E RI -TG C H E M I S T R Y impossible t o detect this form of adulteration b y any of t h e regular methods of analysis, for nothing has been taken away from t h e original apple juice except t h e alcohol, a n d t h a t is replaced either with other alcohol or its equix-alent of acetic acid. -4 vinegar of this kind, however, contains either no volatile reducing substance or only a trace, due t o t h e small amount present in t h e distilled vinegar, as t h e original apple juice has never undergone t h e acetic fermentation. a t which stage t h e volatile reducing substance is formed. For this reason t h e adulteration can be readily detected. SATIONAL FOOD MANUFACTURERS’ LABORATORY ROCHESTER, N E W YORK
CHEMICAL STUDIES ON THE LIME SULFUR-LEAD ARSENATE SPRAY MIXTURE By JV E R u m Received July 14, 1913
PREVIOUS W O R K
1Iuch experimental work has been done with arsenicals of various kinds in t h e way of spraying tests a n d methods of preparation; most of this, however, has been carried on b y horticulturalists and entomologists. Some work has been done with lime sulfur, with a view t o methods of preparation a n d t h e forms of combination in which t h e sulfur is present in solution. N o r e of t h e latter work has been performed by chemists. As far as known a t present, Bradley’ a n d T a r t a r 2 have made t h e only studies of lime sulfur a n d lead arsenate mixtures from a chemical standpoint. Their work consisted of comparing t h e neutral mith t h e acid lead arsenate when mixed with lime sulfur. T h e y compared t h e total sulfur a n d calcium content of t h e lime sulfur b u t made no s t u d y of t h e various forms of sulfur in solution before a n d after mixing. E X P E R I $1 E N T A L
CHASGES.-TOevery one who has handled lime sulfur a n d lead arsenate in a mixture for one spraying, it is a well knonm fact t h a t a change occurs in t h e appearance of lead arsenate. T h e white lead arsenate very soon becomes black in presence of lime sulfur solution. If a solution of lead acetate be added t o a solution of sodium thioarsenate a precipitate when first formed has a reddish yellow color which very soon gives way t o a darker brown a n d this in t u r n t o a very dark gray-almost black. Sei-era1 drops of concentrated lime sulfur solution added t o a small q u a n t i t y of fine particles of lead arsenate suspended in water will result i n t h e lead arsenate undergoing t h e same color changes described above i n t h e precipitation of t h e lead thioarsenate. With t h e addition of t h e first lime sulfur solution t h e particles of lead arsenate t u r n t o t h e reddish yellow color a n d i n t h e presence of more lime sulfur i t t u r n s darker a n d finally black in t h e excess of lime sulfur. Again if t h e lime sulfur be added t o t h e lead arsenate in t h e water in small diluted portions, up t o a certain point t h e sulfur will be precipitated so as t o decolorize completely t h e solution a n d beyond t h a t point t h e color of f u r t h e r additions of lime sulfur apparently is not affected. COLOR
1 2
THISJOURNAL. 1, 606. I b i d , 2, 271, 3 2 8
EFFECT
Oh- L E A D
OF
ARSESATE
847
MIXING
IVITH
LIME
SULFCR SOLCTIOS
At first i t was attempted t o mix small definite quantities of lead arsenate with accurately measured portions of lime sulfur solution so t h a t definite quantities of lead a n d arsenate could be accounted for after mixing with lime sulfur. This, however, was abandoned, because i t was found impractical t o separate t h e black leadarsenate-sulfur residue quantitatively from t h e filter upon which i t was separated a n d washed from t h e lime sulfur. T o avoid this difficulty, quantities of approximately one hundred grams of lead arsenate were mixed with lime sulfur. (Lime sulfur concentrate 32.5’ B., diluted I t o 40, about t h e concentration recommended for summer spray.) The mixture was prepared from Grasselli commercial lime sulfur a n d Sherwin Williams “Xew Process” lead arsenate which was slightly acid t o litmus. The latter showed t h e following analysis, d r y basis: Total lead (Pb) Per cent 64 18
Total arsenic oxide oxide (AszO.) Per cent
Water-soluble As*Os Per cent
26 42 2 6 52
0.42 0.46
64.28
The lime sulfur was used in large excess in a n att e m p t t o simulate conditions t h a t obtain in spraying. The mixture mas very frequently stirred t o prevent t h e caking t h a t is so common with lead arsenate in lime sulfur. After standing several hours t h e leadarsenic-sulfur residue was filtered with suction a n d washed with previously boiled a n d cooled water t o t h e complete disappearance of color of lime sulfur solution, a n d t h e n with several hundred cc. more of water t o insure complete removal of lime sulfur. The residue was dried in a n oven not over 4oOC. a n d kept in a vacuum desiccator until ready for analysis. One-gram samples were digested with IOO cc. of approximately I O per cent nitric acid solution on t h e steam b a t h for several hours; filtered, washed and t h e digestion repeated. The solution contained t h e lead arsenic and calcium. I t was transferred t o a 300 cc. volumetric flask. diluted t o t h e mark a n d aliquots used for determining t h e lead a n d arsenic. The lead was determined from t h e solution b y t h e chromate method a n d t h e arsenic b y t h e modified Gooch and Browning method. One preparation of t h e mixture gave t h e following results for lead a n d arsenic oxide: Lead (Pb) Per cent 1.........................
2.......................... 3......................... 4...
......................
42.61 42.17 42.24 42.28
ilrsenic oxide (AstOr) Per cent 8.8i 9.06 8.86 8.89
A second preparation gave t h e following by t h e same method: Lead (Pb) Per cent 1.......................... 2..........................
45.52 45.72
Arsenic oxide (.4s20r) Per cent 9.09 9.09
T h e total sulfur, free sulfur a n d calcium were rJso
&
T H E J O V 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
848
determined in t h e second preparation, showing t h e following: ’
Total sulfur Per cent
1 . . . . . . . . . . . . . . . . . . 22.51 , , . , , , , , , , , . 22.52
2..,..
Free sulfur Per cent
Total calcium Per cent
19.32 19.56
5.14 5.02
Total sulfur was determined b y t h e Fresenius’ method, t h e arsenic being removed from t h e hydrochloric acid solution with HIS. T h e calcium was determined b y t h e Rose2 method of decomposition with chlorine a n d separation of lead a n d arsenic b y hydrogen sulfide. Free sulfur was determined b y carbon disulfide extraction. The decrease in percentages of lead a n d arsenic from those of t h e original lead arsenate t o t h e percentages in t h e mixture is very marked. The decrease is apparently due t o t h e addition of sulfur a n d calcium t o t h e mixture. B u t t h e results of analyses do not total a hundred per cent, as shown below: ’
Pb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Totals ............................. Ca . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
AsrOs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
45.62 22.51 5.08 9.09 82.30
This evident loss caused t h e writer t o t r y some method of examining t h e mixture for t h e presence of oxygen compounds of sulfur such as sulfates, sulfites or thiosulfates. Accordingly, one-gram samples were placed i n t h e shaker bottles with about 800 cc. of previously boiled a n d cooled distilled water, shaken for four hours a n d filtered. These solutions were made up in liter flasks a n d aliquots used in analyses. Solutions gave strong tests for calcium with ammonium oxalate, as well as a test for thiosulfate, b u t no evidence of sulfide, sulfites or sulfates. The solutions decolorized iodine solution b u t when bleached again with stannous chloride gave no precipitates with barium chloride in hydrochloric acid solution (even after long standing), t h u s eliminating presence of sulfites or sulfates. A portion of t h e solution boiled with hydrochloric acid became cloudy i n appearance, due t o free sulfur precipitating from t h e decomposition of thiosulfate. Other portions of t h e solutions mixed with chlorine water a n d allowed t o s t a n d over night, t h e n boiled a n d acidified with hydrochloric acid, gave liberal precipitates of barium sulfate indicating t h e thiosulfate. Quantitative determinations of sulfur by t h e latter described method a n d calculated for t h e whole solutions gave t h e following results: NO.
1......................... 2........
.....
3......................... 4......................... 5 ......................... 6 ......................... 7 ......................... 8.........................
Free sulfur Gram 0,0188 0.0185 0,0176 0,0194 0.0162 0.0159 0.0162 0.01i2
Calculated equivalent of CaSnOa
Gram 0.03324 0.04255 0.04048 0,04462 0.03i26 0,03657 0.03726 0.03956
The amounts of calcium thiosulfate shown here 1 2
Treadwell and Hall, p. 357, Vol. 11, 3rd ed. Ibid.. p. 359.
Vol. 5 , S o .
IO
calculated t o t h e original weight of t h e sample show from three a n d three-tenths t o four a n d four-tenths per cent thiosulfate present. T h e solutions showed only traces of arsenic, so t h a t very small quantities of calcium arsenate could possibly be present. The Cornel1 Station’ has shown t h a t mixing lead arsenate with lime sulfur increases t h e fungicidal value of lime sulfur. Haywood* i n his work on lime sulfur says: “ I t is a well known fact t h a t sulfites a c t as antiseptic agents. There is reason t o believe t h a t they would also act as insecticides. F r o m t h e decomposition of t h e wash there are obtained sulfur in a very finely divided form, thiosulfate for a time, a n d sulfite which is gradually set free. T h e writer (Haywood) is of t h e opinion t h a t these are t h e active agents in killing insects.” Haywood shows b y reaction how t h e thiosulfates are formed from t h e polysulfides. If i t is true, as he supposes, t h a t t h e fungicidal properties of lime sulfur are largely due t o t h e formation of thiosulfates a n d sulfites with liberation of free sulfur, here t h e n is a n explanation, partially a t least, for t h e increase of t h e fungicidal properties of t h e lime sulfur solution when mixed with lead arsenate. Bradley a n d T a r t a r 3 s t a t e t h a t no sulfides of arsenic are formed since t h e y would be soluble in t h e alkaline lime sulfur solution, b u t none were found in t h e solution. The writer also failed t o find a n y sulfide of arsenic in t h e lime-sulfur solution. If a portion of t h e lead arsenate-sulfur residue be covered with a I O per cent sodium hydroxide solution, t h e n warmed on t h e steam b a t h for a short time a n d allowed t o settle, some of t h e supernatant liquid when acidified with hydrochloric acid will be shown t o cont a i n arsenic sulfide. A small quantity will be thrown o u t of solution. A p a r t of t h e residue remaining after extraction for free sulfur was treated with t h e alkali, b u t t h e solution gave no precipitate of arsenic sulfide when acidified. A second portion of t h e residue which h a d been extracted until free from sulfur was warmed with sodium polysulfide. After standing several hours on t h e steam b a t h t h e liquid gave quite a heavy precipitate of arsenic sulfide when acidified with hydrochloric acid. Arsenic in t h e arsenic sulfide precipitates was verified b y boiling with hydrochloric acid a n d potassium chlorate a n d precipitating as magnesium ammonium arsenate. EFFECT OF M I X I N G O N L I M E S U L F U R
T o observe t h e effect of mixing on t h e lime sulfur solution approximately one-gram samples of t h e lead arsenate dried free from moisture were mixed with accurately measured quantities of t h e lime sulfur solution (concentrate 32.j’ B. used in different dilutions). T h e mixtures were made in small ground glass stoppered flasks t h a t were filled by t h e quantities of lime sulfur used so as t o exclude all air possible. T h e lime sulfur was separated from t h e lead arsenate residues b y means of Gooch filters. Aliquot p a r t s of I O cc. were immediately drawn off, a n d t h e del 2
Wallace, Blodgett and Hesler, Cornell Sta., Bull. 290. Haywood, Bureau of Chem., U. S. D . A , Bull. 101.
3 LOC.
Lit.
OCt., I913
T H E J O U R N A L O F I N D L ’ S T R I A L A N D E N G I iV E E RI X G C H E M I S 2’R Y
849
termination of total sulfur made from one, a n d t o t a l TABLEI-ANALYSES OF LIME S U L F U R S O L U T I O N WITH LEAD ARSENATE STANDING ONE H O U R . WEIGHTSOF VARIOUSFORMS OF SULFUR IN sulfides, thiosulfate, sulfite a n d sulfate all made from a GRAMS second p a r t . 1 7 3 4 5 6 , T h e monosulfide sulfur was not determined b u t total sulfide sulfur was precipitated b y iodine solution, determined as barium sulfate a n d t h e iodine titration continued for thiosulfate as described b y Harris.’. As comparative results were sought in t h e lime I . . . 0.51200 0,00281 0.03477 0.34958 0.32964 1.0006 0.09539 sulfur before a n d after mixing with lead arsenate t h e 2 . . . 0,30066 0.00309 0.03635 0.34010 0.32031 0.9997 0.09333 above method was found very satisfactory a n d quick Lost 3 . . . 0.29922 0.00295 0.03635 0.33852 0.32243 1.0013 Blank(a) for precipitating t h e sulfide sulfur. 0.12116 4 . . . 0,42132 0,00116 0,01738 0.43986 0,43735 None After t h e thiosulfate titration t h e sulfide sulfur was 5 . . . 0,23245 0.00178 0.03984 0.27407 0.24525 0.0128 0.07817 filtered off, a n d sulfites, now oxidized t o sulfates, along 6 . . . 0.20834 0.00178 0.03824 0.24836 0.22105 1 , 0 0 1 5 0.08141 7 . . . 0.21020 0.00178 0.03984 0.25182 0.22222 1.0013 0.07434 with a n y sulfates originally present, were precipitated 8... 0.20607 0.00175 0.03984 0.24766 0.22002 0.9996 0.07640 as barium sulfate in the cold hydrochloric acid solution 9. . . 0.21844 0,00179 0.03984 0,25907 0,23478 1.0203 0.07537 by standing a t least twelve hours. 10. . . 0.21246 0.00178 0.03824 0.25248 0.22846 1 0088 0.07611 Blank(a) T h e results of analyses of lime sulfur mixed with 11... 0.38680 0.00104 0.02231 0.41015 0.38859 None 0.11791 lead arsenate as described above are shown below in (a)The “blank” determination before mixing is for the same quantity Tables I a n d 111. Those shown in Table I are for of the same lime sulfur solution used in the mixtures given immediately mixtures standing one hour a n d Table I11 shows above. results for mixtures standing overnight. Tables I 1 TABLE11-DIFFEREXCESI N G R A M 5 I N TABLE1 FOR W H O L E AJIOUNT OF LIMES U L F U R U S E D B E F O R E A N D AFTER MIXING(1 HOUR) a n d I V show t h e differences in t h e various forms of 1 2 3 4 5 6 sulfur, being more or less, as t h e case m a y be, t h a n in Difference t h e original lime sulfur solution before mixing with .-: between to’’( ii tal S deter95 d lead arsenate. % mined and % 2 .a Tables I1 a n d I V show losses of sulfide sulfur a n d * total S calYa 2 calcium from solutions a n d increases of thiosulfate culated. .-2W LC L 4 17 -I Gain $ ’ a n d sulfate (including sulfites) in every case. Mixtures ; I ! 0.00165 0 . 0 1 739 0.01994 1 ,0006 0.02577 l . . . . . . 0.10932 Xos. I, 2, 3, i n both Tables I a n d I11 were made at 0.00193 0 . 0 1897 0.01979 0.9997 0.02783 2 . . . . . . , 0.12066 t h e same t i m e from t h e same diluted lime sulfur solu0,001 79 0,01897 0.01609 1.0013 Lost 3 . . . . . . , 0.12210 0.00074 0.01753 0.02882 1.0128 tion with approximately t h e same weights of lead 5 . . . . . . . 0.15435 0.03974 0.02731 0.01 593 0,00074 0.03650 1.0015 6 . , . .. . . 0,17846 arsenate as shown in t h e tables. T h e results in t h e 0.02960 0.01753 0.00074 0,04357 1.0013 7 . . . . . . . 0.17660 first three mixtures, Table I, show t h a t t h e thiosulfate 0.0007 I 0.02764 0.01753 0.04151 0,9996 8 . . . . . . . 0.18073 0.00075 0.02429 0.01753 1 ,0203 0.04254 9. . . . . . . 0.16836 in solution is increased in t h e lime sulfur b y mixing 0.00074 0.01593 0.02402 1 ,0088 0 04180 I O . . . . . , , 0.17434 as well as t h e sulfate (including sulfites), b u t upon further examination of I , 2 , 3, Table 111, i t will be TABLE111-ANALYSES OF LIMES U L F U R S O L U T I O N WITH LEAD .kRSENATl% S T A N D I N G O V E R N I G H T . W E I G H T S OF V A R I O U S F O R h f S OF S U L F U R I N seen t h a t t h e oxidation has continued-the thiosulfates GRAMS 1 7 3 4 5 6 7 having decreased a n d sulfates increased. It must be borne in mind t h a t t h e flasks were full t o exclusion of air, a n d a n y oxidation could come only from t h e lead arsenate, also t h a t t h e water used in dilution of lime sulfur concentrate h a d been previously boiled t o free i t from air a n d carbon dioxide. I . . . 0.21782 0 . 0 0 3 5 0 0.02687 0.24819 0.25052 1.0024 0.07537 Nos. j t o 14, Table 111, are mixtures made with 2 . . . 0.21391 0.00419 0,02529 0.24339 0,23925 1.0017 0.07493 smaller quantities of a more diluted lime sulfur t o 3 . . . 0.23390 0,00391 0.02055 0.25836 0.26198 1.0021 0.08067 Blank ( a ) observe, if possible, t h e effect of lesser concentration 4 . , , 0.42132 0.00116 0.01738 0.43986 0.43735 None 0.12116 on t h e mixture. I n Table I V i t will be noticed t h a t 5 . . , 0.0364 0.0024 0.0231 0.0619 0 0797 1.0125 ..,. t h e a m o u n t of sulfide sulfur lost from t h e weaker 6 . . . 0.0362 0.0020 0.0231 0.0613 0.0770 1.0194 .... j... 0,0352 0.0022 0.0245 0,0619 0.0782 1.0122 .... solution approaches very closely t h e a m o u n t lost from 8 . . 0,0352 0.0021 0.0191 0.0564 0 0669 1.0065 .... solution in t h e more concentrated form. The sulfide Blank (a) 0.2299 0.2269 hTone . . 0.0010 0.0127 9.. . 0.2162 sulfur loss is due to precipitation in some form b y t h e 1.0007 .... 0.0031 0 0167 0.0805 0.0860 I O , . . 0.0607 lead arsenate as well as t h e formation of thiosulfates 0.0175 0,0892 0.0946 0 9994 ... 0.0029 11. . . 0.0688 a n d sulfates from t h e sulfides. 0.0159 0.0929 0.01)69 1.0072 . ... 0.0031 12.. , 0.0739 .. T h e loss of c,alcium from t h e solution apparently 13.. , 0 . 0 6 4 8 0 , 0 0 3 2 0.0159 0.0839 0 . 0 9 1 7 1.0289 is due t o only partial solubility of t h e calcium thio- 14.. .Blank(a) 0.2448 0.0010 0.0155 0.2613 0.2680 None sulfate in t h e lime sulfur, as well as due t o a n y small ( a ) The “blank” determination before mixing is lor the same quantity quantities of calcium arsenate t h a t m a y be formed, t h e of t h e s a m e lime sulfur solution used in the mixtures given immediately latter being mostly insoluble in t h e excess of lime sulfur above. solution. sulfur as calculated (shown in column 4 ) is found by I n columns 4 a n d j, Tables I a n d 111, are given t h e summing up t h e three forms of sulfur in solution. t o t a l sulfurs in t h e lime sulfur solutions. T h e total T h e total sulfur shown in column j is t h a t determined directly on a separate portion of t h e solutions. Columns hlich. Sta , Tech., Bull. 6. L
,:
T H E J O C R N A L OF IiVDUSTRIAL A N D EiVGINEERING C H E M I S T R Y
8 50
Vol.
j,
KO. I O
4, Tables I1 a n d IV, show t h e differences between t h e t w o results for total sulfur. T h e difference shown i n Table I1 is indicated as a gain, t h a t is, t h e calculated total shows a gain when compared with total sulfur b y determination. This difference was a t first t h o u g h t t o be due t o analytical error b u t when t h e same comparisons were made for t h e mixtures standing overnight, with only one exception as indicated, t h e calculated totals show a loss as compared with t h e total sulfur as determined direct.
of thiosulfate a n d sulfites, this increase of thiosulfate in lime sulfur upon mixing it with lead arsenate probably explains t h e increased fungicidal value of t h e lime sulfur a n d lead arsenate mixture. In conclusion, t h e writer wishes t o acknowledge his indebtedness t o Dr. A . W. DOX, of this Station, a t whose instigation t h e above work was undertaken.
TABLE IV-DIFFERENCES IN GRAMS IN TABLE I11 FOR THE WHOLEAMOUNT OF LIME SULFUR USED BEFORE A N D AFTEX MIXING (12 HOURSOR
SPONGES AS A FERTILIZER
MORE) 1
2 vi
s 1.. . 2.. 3... 5... 6.. .
.
i... 8... 10. . . 11. . . 12.. . 1 3 . ..
.rj
i’
v?
2
d
0
B a
i
0.20350 0,20741 0.18742 0.1798 0.1800 0.1810 0,1810 0.1841 0.1760 0.1709 0.1800
3
E
* d
c v,
0.00234 0.00303 0.00275 0.0014 0.0010 0.0012 0.0011 0,0021 0.0019 0.0021 0.0022
-2s
L
g
a
e
.a
-r 0.00949 0.00791 0.00317 0.0104 0.0104 0,0118 0,0064 0,0012 0.0020 0.0004 0.0004
4 Difference betweentotal S determined a n d total S calculated
Loss
0.0033 0.00414(a) 0,00362 0.01780.0157 0.0163 0,0105 0.0055 0.0054
4
F
-2
&
2
2 5
i;
‘E
2
c
.o
.P
3 2
0 1.0024 1.0017 1.0021 1.0125 1.0194 1.0122 1.0065 1.0007 0.9994 1.0072 1.0289
0.04579 0.04623 0,04049
......
.. ... . . .. . . .
. .. .. ... . .. .. . . ,..
.
0.0040 0.0078 (a’ No. 2 is t h e only exception in t h e table where t h e total sulfur as calculated by summing up t h e three forms of sulfur showed a gain over t h e total sulfur as determined.
Whether t h e gain as shown by t h e calculated total a t t h e e n d of a n hour is due t o analytical error a n d t h e loss shown b y t h e calculated total of mixtures after long standing is due t o formation of a form of sulfur not included b y t h e present analytical methods, o r whether t h e y are both due t o analytical error, is not understood a n d no explanation is offered for it a t this time. DISCUSSION O F RESULTS
As s t a t e d before, t h e writer failed t o find a n y arsenic sulfide in t h e lime sulfur. B u t t h e evidence presented leads t h e writer t o believe t h a t a small a m o u n t of t h e arsenic oxide is converted into t h e sulfide or t h a t i t forms a thioarsenate possibly with lead which would hold i t insoluble in t h e weaker alkaline lime sulfur solution. T h e close analogy of t h e color changes undergone b y precipitating lead thioarsenate a n d t h a t of mixing lead arsenate a n d lime sulfur led t h e writer t o look for t h e formation of arsenic sulfide. T h e results show t h a t t h e mixing of lead arsenate a n d lime sulfur increases t h e thiosulfates a n d sulfites in t h e residue. If Haywoodl is correct in his view t h a t t h e fungicidal value of lime sulfur is due t o t h e presence
I
AWES
By
JOSEPH
Loggerhead sponge is used with “wonderful results” b y t h e farmers of t h e Florida Keys who “hardly ever use chemical fertilizers” a n d i t “grows in countless thousands in shallow water where it is easy t o procure” as well as t o “ a n enormous size,” according t o Mr. Thomas E. Reedy of Key West. Its use for t h e same purpose b y t h e citrus fruit growers of t h e mainland is attested b y Dr. H. F. l l o o r e , of t h e U. S. Bureau of Fisheries, a n d has been seen b y him growing in such quantities i n t h e salt waters of southern Florida t h a t he has “long thought i t should be exploited.” The claims for i t as a fertilizer are verified by analyses of samples from Key West submitted b y h4r. Reedy, t h e approximate results on air-dry material being 4 per cent of nitrogen, of I per cent each of potash (KzO) a n d phosphoric acid (PnOb), j per cent of lime ( C a 0 1 1 g 0 , mainly CaO) a n d 4 0 per cent organic matter. Mr. T. C. Trescott, Chief of t h e Nitrogen Division of t h e Bureau of Chemistry, very kindly made t h e nitrogen determinations. &Ir. C. F. Miller, of this Bureau, made t h e others, duplicating t h e m b y repetition, a n d t h e y were verified i n p a r t b y t h e writer. Analyses of other non-commercial species a n d of other samples of t h e Loggerhead are desirable although i t is not likely t h a t t h e y differ materially from one another in composition since t h e y all have t h e same general characteristics ,and are developed under practically identical conditions. It is evident from t h e composition of this material a n d from its demonstrated efficiency a s a fertilizer t h a t i t has considerable value t o coast a n d island farmers a n d fruit growers having easy access t o i t wherever i t is found. With a view t o determining t h e feasibility of extending its use, further investigations are in progress a n d contemplated. BUREAU OF S O I L S
DEPARTXENT OF .kCRICULTURE WASHINGTON, D . C.
LABORATORY AND PLANT
THE CHEMICALLABORATORY OF THE PICHER LEAD CO. By JOHN A. SCHAEFFER Received August 18, 1913
T h e completion of t h e new chemical laboratory of 1 LOC.
cir.
G. SMITH
Received Aug. 13, 1913
6
5
AGRICULTURAL EXPERIMENT STATION IOWA STATE COLLEGE
I
t h e Picher Lead Company, located at Joplin, Missouri, marks another advance in t h e construction of industrial laboratories, again showing t h e value of t h e highest t y p e of equipment for scientific investigation which is so essential in t h e control of manufacturing opera-
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