/j /. 1 . 7 ' r J 
 
 Issued Decembei I 
 
 U. S. DEPARTMENT OF AGRICULTURE, 
 
 BURI \r OF PLANT INDUSTRY— Circular No. 43. 
 1'.. 1 GALLON AY, Chief of Bureau. 
 
 THE DETERIORATION OF CORN 
 IN STORAGE. 
 
 J. W. T. DUVEL, 
 
 Assistant i\ Charge of Laboratory Methods, 
 I }r \i\ Standardization. 
 
 
 SHINGIOH : OOVIHNUtNV PHlNTlNG ( ■ 
 
 DC^M^^T" 
 
 DEPOSITORY 
 
 
BUREAU OF PLANT INDUSTRY. 
 
 Chit/ of Bureau, Beverly T. Galloway. 
 Assistant Chief of Bureau, Albert F.Woods. 
 Editor, J. E. Rockwell. 
 CLnf Clerk, James E. Jones. 
 [Cir. 43] 
 
 2 
 
B. P. I. -521. 
 
 THE DETERIORATION OF CORN IX STORAGE/ 
 
 INTRODUCTION. 
 
 In February, L909, special investigations were begun at Baltimore, 
 M<l., in cooperation with the Baltimore and Ohio Railroad Company, 
 for the purpose of obtaining definite information regarding the dete- 
 rioration of shelled corn in elevator bins and in grain cars. The first 
 series of experiments in these investigations comprised tests with (1) 
 5,550 bushels of corn stored in a 65-foot elevator bin for 69 days, 
 until the corn al the top of the bin had become badly damaged; 
 (2) 900 bushels of dried damaged corn from the top of the bin loaded 
 into car No. 67031 and held on the track for an additional 37 days, 
 and (3) 900 bushels of the best cool corn from the same bin loaded 
 into car No. 75197 and held on the track with the <nv containing the 
 dried damaged coin. 
 
 In this preliminary report no attempt has been made to generalize 
 the results of the experiments, to draw any definite conclusion-, or 
 even to give any extended expression of opinion. The aim has been 
 to outline the conditions under which this first series of experiments 
 was made and to give a brief summary of i he results obtained, leaving 
 the individual reader to formulate his own theories until the investi- 
 gations are more advanced. It is hoped, however, that this prelim- 
 inary report will provoke discussion and bring about a better under- 
 standing of the purpose and value of investigations of this character. 
 
 CORN STORED IN ELEVATOR BIN. 
 
 On February 17 and is. 1909, 5,550 bushels of shelled corn were 
 stored in a 65-foot bin b in elevator C of the Baltimore and Ohio Rail- 
 road Company ai Baltimore (Locust Poinl . Md. This corn was left 
 without ''running'' until April 27, 1909, at which time the fermen- 
 tation at the to]) of the hin had progressed so that the corn was hot 
 and sour, the temperature 8 inches belov the surface having reached 
 133 c K 
 
 " This opportunity is taken to acknoM ledge tin- cordial cooperation of the Baltimore 
 and Ohio Railroad Company and the Baltimore Chamber of Commerce, through its 
 grain-inspection department. Special thanks are due to the various men assigned 
 for duly al the elevator, v. ho w illingly rendered e\ cry possible assistance while these 
 experiments were in progress. B. T. Gaixowai Bureau. 
 
 ''The hin in which the corn was stored i- near the center of the outer ro^ of bins 
 
 on the east side of the elevator, il uter 6-inch wooden wall of the hin being built 
 
 against the heavy brick construction of the elevator. 
 [ fir. 43] 
 
THE DETERIORATION OF CORN IN STORAGE. 
 
 The corn used in these experiments was taken from cars selected 
 from those received at Baltimore, Md., on February 16, 1900. So 
 far as the records available show, 4,050 bushels of tins corn were 
 growm in the Dakotas, the remaining 1,500 bushels having originated 
 in Illinois. The 3,050 bushels first run into the bin consisted of 
 practically all Dakota corn. The next draft of 500 bushels was 
 Illinois corn with a small admixture of Dakota corn. The 1,000 
 bushels following consisted of Illinois corn, wdiile the 1,000 bushels 
 in the tenth and eleventh drafts at the top of the bin were composed 
 of corn from the Dakotas. 
 
 In filling the bin each draft consisted of 500 bushels, with the 
 exception of the first 50 bushels at the bottom of the bin. After 
 almost every draft, samples were taken with a 4-foot grain trier, 
 one from the center and one from near each corner of the bin, and 
 the different factors representing the quality and condition of the 
 corn were determined for each sample. The average results of the 
 analyses of the samples representing the different drafts are given 
 in Table I. These results show the moisture content; weight per 
 bushel; weight of 1,000 kernels; sound corn; damaged corn; other 
 grains; dirt, cobs, etc.; badly broken corn; and germination of whole 
 kernels. A comparison of Table I with figure 1 will show the exact 
 location of the corn in the bin represented by each set of averages 
 given in the table. 
 
 Table I. — Average condition and quality of the -5,550 bushels of corn at the beginning 
 of the experiment, as shown by the analyses of samples taken with a 4-foot grain trier 
 after the different drafts were emptied into the bin a 
 
 No. of draft. 
 
 Amount 
 of draft. 
 
 Moisture 
 content. 
 
 Weight 
 
 per 
 bushel. 
 
 Weight 
 of 1.0(H) 
 kernels. 
 
 Sound 
 corn . 
 
 Dam- 
 aged 
 grains. 
 
 Other 
 grains. 
 
 Weeds, 
 cobs, 
 dirt, 
 etc. 
 
 Badly 
 broken 
 corn. 
 
 Germina- 
 tion of 
 whole 
 
 kernels. 
 
 (Bottom) 
 
 1 
 
 Bus. 
 50 
 500 
 500 
 500 
 500 
 500 
 ;,oii 
 500 
 1 000 
 500 
 500 
 
 /'. ct. 
 17.8 
 17.9 
 17.8 
 17.9 
 18.0 
 17.8 
 18.8 
 17.5 
 17.0 
 is 6 
 18.3 
 
 Lbs. 
 53.5 
 53.8 
 53.6 
 53.3 
 
 52. 6 
 53.6 
 53.0 
 54. 5 
 55.0 
 
 53. 3 
 52. X 
 
 Grams. 
 280 
 294 
 337 
 295 
 303 
 296 
 
 L'S6 
 
 317 
 330 
 
 272 
 276 
 
 P. ct. 
 97.9 
 97.6 
 97.4 
 96.9 
 
 96. 2 
 96 i, 
 U7.7 
 
 97. 6 
 96.9 
 96.3 
 96.6 
 
 P.ct. 
 
 0.8 
 1.0 
 
 .5 
 1.4 
 2.5 
 2.2 
 1.8 
 1.3 
 
 .7 
 1.4 
 1.6 
 
 P.ct. 
 
 0.5 
 
 .9 
 
 1.2 
 .9 
 .4 
 .4 
 . 1 
 .5 
 
 1. 1 
 
 .9 
 
 P.ct. 
 0.8 
 .5 
 .9 
 .8 
 .9 
 .8 
 .4 
 .6 
 2.4 
 1.2 
 .9 
 
 P.ct. 
 2.4 
 3.1 
 3.3 
 2.0 
 3.5 
 3.3 
 1.4 
 3.5 
 5.4 
 3.9 
 3.7 
 
 P.ct. 
 
 2 
 
 vl. 3 
 
 3 
 
 4 
 
 72.8 
 73.0 
 
 5 
 
 77.3 
 
 6 
 
 7 
 
 8 and 9 
 
 10 
 
 69 ii 
 87.8 
 95.0 
 
 71. S 
 
 11 
 
 73.0 
 
 
 
 Average 
 
 17.8 
 
 53.7 
 
 301 
 
 97.0 
 
 1.4 
 
 0.6 
 
 1.0 
 
 3.0 
 
 80.6 
 
 
 
 a All figures in the table other than those in the first two columns represent averages, so thai the final 
 average of all the com in the bin is based on a total of 43 samples, or 1 sample lor approximately every 
 130 bushels of corn emptied into the bin. 
 
 As will be seen from the table, the average moisture content of 
 
 the corn in the different drafts varied from 17 per cent in the eighth 
 
 and ninth to 18.8 per cent in the sixth draft, with an average of 
 
 17.8 per cent for all of the corn in the bin. The weight per bushel 
 
 [Cir. 43] 
 
Till. DETERIORATION OF CORN [N STORAGE. 5 
 
 varied from 52.6 pounds in the fourth drafl to 55 pounds in the 
 eighth and ninth, with ;t total average of 53.7 pounds. Similar 
 variations are shown in the other factors, mosl of which indicate 
 thai the corn of the highest quality and in the besl condition was 
 
 the Illinois coin contained in the eighth and ninth drafts. 
 
 NOTES ON THE TEMPERATURE AND THE CONDITION OF THE CORN 
 
 w l\ THE BIN. 
 
 The bin usvA in this experiment was previously equipped with 
 
 thirteen electrical resistance thermometers, so that temperature 
 records of the coin in various parts of the bin could be taken at any 
 time during the course of the experiment. Thermometer No. 1 was 
 ahont :\\ feel from the bottom, near the center of the hopper. The 
 other thermometers were distributed through the center of the corn, 
 approximately 8^ feel apart, excepl that in the corn near the top 
 of the bin, where deterioration is most likely to begin, additional 
 thermometers were placed at various points. Figure I shows the 
 location of these thermometers, numbered from 1 to 7 and from A 
 to E, inclusive. In this same diagram are also shown the number 
 of bushels contained in each draft, the average moisture content 
 and the weight per bushel of the corn in the various parts of the bin 
 at the time of filling, the temperature of the corn immediately after 
 the bin was filled, and the maximum temperature of the corn at the 
 end of the experiment, which extended over a period of 69 days. 
 
 The temperature of the coin immediately after the bin was Idled 
 varied from 36 to in K. As the bin was being filled the atmosphere 
 was dear and dry. the relative humidity being 18 per cent. The 
 temperature of the air in the elevator varied from 3G° to .",'.' I . 
 "While i he corn w as in storage, temperal tire readings were made e\ ery 
 two or three days until April 22, when the corn at the top of the bin 
 gave evidence <r{ very rapid deterioration, necessitating frequent 
 readings during t be remaining five da\ s of 1 be test . 
 
 The lirst indication that the corn had begun to deteriorate was on 
 the 26th of March, alter it had been in storage 37 days, at which time 
 a slight ly sour odor was perceptible in the corn at t be top of the bin, 
 showing that fermentation had begun. The highest temperature 
 recorded at this time was 12° V.. by thermometer < . approximately 
 5 feel below the surface of the corn. From this time on the increase 
 in the temperature of the 500 bushels of corn at the top of the bin 
 became more pronounced. However. 27 days later, on April 22, the 
 highesl temperature recorded was still less than 70 I-'., hut during 
 the 5 days mi mediately following a maximum of L33 V. was reached, 
 8 inches I. clow the surface of the grain. 
 
 [Clr.43] 
 
THE DETERIORATION OF CORN IN STORAGE. 
 
 sW/RE CABLE 
 
 CORNER '2 
 
 /& 3% MO/STURE. 52.8 L6s. per Bu. 
 TEMPERATURE 38° to /33°F 
 
 /8.6% MO/STURE. 53.3 Lbs. per Bu. 
 TEMPERATURE 38°to //5°E 
 
 /70% MO/STURE. 55.0 Lb s. per Bu. 
 TEMPERATURE 38° to 56.5° E 
 
 17. 5°/o MOISTURE. 54.5 Lbs. per Bu. 
 TEMPERATURE 40° to 40. 5° E 
 
 /8. 8 % MOISTURE. 53. Lbs. per Bu. 
 TEMPERATURE 36.5° to 41. 5°E 
 
 17.8 %M0ISTURE. 53 6 Lbs. per Bu. 
 TEMPERATURE 36 ° to 40. 5°E 
 
 Y8. % MO/STURE. 52. 6 Lbs. perBu. 
 TEMPERATURE 36° to 39. 5° E 
 
 179 °/o MO/STURE. 53.3 Lbs per Bu. 
 TEMPERATURE 36° to 40.5 °E 
 
 /7 8% MO/STURE. 53.6Lbsper Bu. 
 TEMPERATURE 38° to 4-/.5°E 
 
 /7.9 % MO/STURE. 53. 8 Lbs per Bu. 
 TEMPERATURE 36° to 4/.5°E 
 
 /78°/o MO/STURE. 53.5 Lbs. per Bu. 
 TEMPERATURE 36° to 4-/.5°E 
 
 Fig. 1. — Diagram showing the position of the thermometers; the number of bushels, the moisture con tent, 
 and the weight per bushel for each draft; and the temperature of the corn at the beginning and at the 
 end of the experiment. 
 rCir. 43] 
 
CHE PI. I ERIOB \ i [ON 0] CORN IN STORAGE. 7 
 
 On March •'!! three holes were bored through the wall of the bin on 
 the side nearest the interior of the house. One hole was bored 
 
 approximate^ 10 feel from the bottom, another 25 Feel fr the 
 
 bottom, and the third 10 feet from the bottom of the bin, or 20 feel 
 from the top of tin* grain. Samples taken through these holes with 
 a 4-foot grain trier showed thai the corn had not changed materially 
 since it was first placed in the bin, no unnatural odors being percep- 
 tible. On the --a i ue date samples taken with a long grain t rier from 
 7 feet below the surface showed the corn at that point to be slightly 
 musty. 
 
 Samples taken on April 3 from 3, 7. and 12 feet below the surface 
 showed mure pronounced odors in the corn at 3 and 7 feet, but no 
 odor could be detected in t he samples t aken at 12 feet . At t bis t ime 
 the maximum temperature of the corn l_' feel below the surface was 
 42 !•'. The highest temperature in the upper 500 bushels was l.V. ~ 
 F. On April 6 the corn near the top of the bin was \ er\ musty, 
 although the maximum temperature was onlj is !•'. On April 13, 
 samples were again taken from 12 feet below the surface but revealed 
 qo odors indicating deterioration. 
 
 On April 19 the maximum temperature in the 500 bushels of corn 
 at the top of the bin was (ill V., as registered by thermometer A. 8 
 inches below the surface. The corn near the top at this time was 
 very musty and a considerable quantity of fresh mold was growing on 
 the kernels. The temperature of the corn 12 feet below the surface. 
 as registered l>\ thermometer .1, was 56° F., which was within one- 
 half degree of the highest temperature recorded at that depth during 
 the cut ire test . 
 
 On April 26, samples were again taken through the holes in the 
 side of the bin at 1 I), '_'.">, and 10 feet from t he holt mn, together with a 
 number of samples represent ing t he 1 ,000 bushels at t he top of the bin. 
 At this time the com at the top of the bin was hot, musty, and sour, 
 but no odor could be detected on the samples taken through the hole 
 in feel from the bottom of the bin. However, the samples taken 
 through the holes 25 and 10 feel from the bottom of the bin showed 
 that the corn near the bin walls at those points was slightly sour. 
 This condition was shown more clearly when the bin was emptied 
 the Following day. the corn having a tendency to adhere to the sides. 
 In emptying the bin the corn from the sides became unevenly mixed 
 with the better corn from the interior, so that an odor was percep- 
 tible on a considerable portion of the entire hulk. 
 
 The fermentation in the upper 500 bushels of com was \er\ active 
 
 at this i me and the temperature was increasing rapidly. On April 
 
 25 thermometer No. 7. in the center about 5 feel beneath the surface 
 
 of the com, registered s 7" V. At 8 o'clock the following morning 
 
 [t'e 
 
8 
 
 THE DETERIORATION OF CORN IN STORAGE. 
 
 this same thermometer registered 102°; at 11.45 a. m., 105°; at 3.10 
 p. m., 107°. and at 9 o'clock the morning of the 27th, 115°, an increase 
 of 28 degrees F. in 48 hours. The highest temperature registered on 
 April 27 was 133° F., in corner No. 4, 8 inches below the surface of 
 the corn. In corner No. 1, 14 inches below the surface, the tem- 
 perature was 110°; in corner No. 2, 112°; in corner No. 3, 125°: and 
 in corner No. 4, 132+°. Thermometer B, in corner No. 2, the same 
 depth below the surface as thermometer No. 7, registered 71.5° F. 
 
 1909. FEBRUARY 
 
 MARCH. 
 
 APRIL. 
 
 1909. 
 
 Ill ■!■■ I 
 
 WEATHER RECORD. 
 
 IB 
 
 -fi^/N OR SNOW, .01 fNCH OR MORE. \ \ = RAIN OR SNOW, TRACE. 
 
 I 1= NO RAIN OR SNOW. 
 
 Fig. 2. — Diagram showing the temperature of the corn in various parts of the bin. the daily maximum and 
 minimum air temperature, and the precipitation from February 17 to April 27, 1909. 
 
 A clearer understanding of these conditions will be had by consult- 
 ing figure 2, which shows the temperature of the corn in various parts 
 of the bin, together with the daily maximum and minimum air tem- 
 perature, and the general character of the precipitation during the 
 GO days covered by the experiment. 
 
 CONDITION OF THE CORN AT THE END OF THE EXPERIMENT. 
 
 As shown in figure 2, the only marked increase in temperature was 
 in the G or 7 feet of corn at the top of the bin. The maximum tem- 
 perature registered by thermometers No. 6 and A, approximately 12 
 
 [Cir.43] 
 
Ill I . DETERIORATION OF CORN IN STORAGE. \) 
 
 feel below the surface, was 51 and ">f>\ !•'.. respectively. The tem- 
 perature of the corn in the lower pari of the bin varied from 39-J° to 
 4H° V., as compared with a variation of from 36° to 40° F. at the 
 beginning of the experiment. 
 
 The moisture content of the corn immediately at the surface was 
 14.95 per cent, <>r .'>..!"> per cent less than on February 17. The 
 moisture content of the 1,000 bushels at the top of the bin, exclusive 
 of the corn on the surface, was slightly higher than when the corn was 
 placed in the bin, showing that the deterioration of the corn was 
 resulting in the formation of more water than was being given off by 
 evaporat ion. The weight per bushel of the surface corn was 5 I pounds, 
 while the weighl of the remainder of the upper 1,000 bushels had 
 decreased from 53 to 51 pounds. 
 
 The germination of the poorest corn from the top of the bin varied 
 from to 17 per cent, with an average of 10.3 per cent, as compared 
 with an average of 7_\ 4 per cent on February 17. This corn was 
 damaged so that many of the germs were badly discolored. The 
 average germination of the 1,070 bushels taken from the top of the 
 bin for further experiment, which included not only the hot corn 
 hut all that had a temperature over 50° F., was 42.6 per cent after 
 being handled, dried, and loaded into car No. ti7(): J >1. 
 
 The corn in the lower 1") feet of the bin, except !»()() bushels of the 
 best quality which was loaded into car No. 7.">1!)7 for further test, 
 after being handled over three elevators and dried to 1 L87 per cent 
 of moisture, was given a grade <>f "Mixed corn." The germination 
 of this corn was SO.S per cent at the beginning of the experiment, 71.4 
 per cent when drawn from the bin, and 81.4 per cent after being 
 handled and dried. 
 
 The total loss in weight, as shown by the certificates furnished by 
 the weighman of t he ( Jhamber of Commerce, resulting from filling and 
 emptying the bin and the evaporation during the (>'.» days in storage, 
 amounted to 310 pounds, or slightly less than one-tenth of l per cent. 
 
 DRIED DAMAGED CORN FROM TOP OF BIN STORED IN CAR. 
 
 The 1.1)7(1 bushels of corn drawn from the top of the bin was 
 weighed, handled over three elevators, and reweighed, after which 
 it was artificially dried in a grain drier at a temperature varying from 
 151 to 163 I-'. The average moisture content of this corn as taken 
 
 from the bin was 18.64 per cent. The average moisture content 
 when emptied into the drier was 18.30 per cent, of ; , reduction of 
 i).:; i of 1 per cent a- a result of the handling, which i^ equivalent to 
 a loss in weight of u. i ,,|' i per .-cut. In drying, the moisture con- 
 
 Bureau "i' I'l.mi Industry . U. S. Dept. of Agriculture, entitled "Mois- 
 ture Contenl and Shrinkage in Grain," explains why this dil cists and how it 
 
 is calculated. 
 
 [CIr. i:i] 
 
10 THE DETERIORATION OF CORN IN STORAGE. 
 
 tent was reduced from 18.3 per cent to 14.57 per cent, a reduction of 
 3.73 per cent, which is equivalent to a loss in weight of 4.44 percent. 
 
 After this corn was dried and thoroughly cooled, 900 bushels, having 
 an average moisture content of 14.57 per cent, were loaded into car 
 No. 67031 as if intended for shipment. The car was run out into the 
 yard and left standing on the track fully exposed to all atmospheric 
 changes. The temperature of this corn immediately after it was 
 loaded into the car, after drying and cooling, on April 27, varied from 
 57° to 58° F. Frequent temperature readings were made up to and 
 including May 25, when the highest temperature at any point in the 
 corn was 66° F., an increase of only 8 or 9 degrees, although the 
 temperature of the air in the car had varied from 56° to 82° F. 
 and the temperature of the air outside of the car from 41 ° to 90° F. 
 On May 25, after being in the car 28 days without any noticeable 
 change in condition, the corn was unloaded, elevated, and weighed, 
 and then returned to the car and left an additional 9 days on the 
 track. The air temperature at this time was 73 ° F. , resulting in a very 
 slight increase in the temperature of the corn by the time it was 
 returned to the car. 
 
 On June 3 the temperature of the corn was 67° F., an increase of 
 only 10 degrees during the entire 37 days that this corn was in the 
 car. The condition of the corn was fully as good if not better than 
 when it was placed in the car on April 27, although the odor resulting 
 from the fermentation of the corn while in the bin had not entirely 
 disappeared. 
 
 On June 3 the moisture content of the corn on the surface was 13.1 
 per cent, with 14.48 per cent for the remainder of the corn in the car, 
 a difference of 1.38 per cent in the moisture content, which is equiva- 
 lent to a shrinkage in weight in the surface corn of 1.59 per cent in 9 
 days from May 25 to June 3. 
 
 UNDBIED CORN FROM BIN STORED IN CAR. 
 
 In order to secure data for comparison, 900 bushels of the best cool 
 corn from the bin, principally the Illinois corn from the eighth and 
 ninth drafts, were loaded into car No. 75197 and placed on the track 
 alongside of the car containing the 900 bushels of dried damaged corn 
 from the top of the bin. The temperature of this coin while still in 
 the bin varied from 40° to 42° F., but in "running" from the bin, 
 elevating to the scale, and loading into the car, the temperature 
 was increased so that the temperature of the corn after being loaded 
 was 48° F. The air temperature at this time was 51 ° F. and the rela- 
 tive humidity of the atmosphere 70 per cent. The average moisture 
 content of this car of coin was 17.5 per cent, and the weight per 
 bushel was 55.3 pounds. 
 
 | CIr. 131 
 
I II I |i| II RIOB \ I [OK OF CI >i:X IN STOB \.GI . 
 
 11 
 
 On M;i\ 20, after standing on the track 23 daj s, the corn in this car 
 began to show unmistakable signs of deterioration. At that time the 
 maximum temperature of the corn was 75 !•'.. and it had a distinctly 
 Mini- an. I musty odor. Five days later the maximum temperature 
 was L22 I' - . in the brake end of the car, approximately 6 inches below 
 the -hi face of the corn. Tin' a\ erage weight per bushel had decreased 
 from •">■">.•'! pounds to 52.6 pounds. The moisture content varied from 
 13.6 per cent in the corn at the surface to 17..") per cent where the 
 tempera! lire was 1 '_''_' F., as compared with a varial ion of from 17 per 
 cent tu 17. 7 per cent at the time the corn was loaded into the car. 
 
 Z8 o*rs 
 
 *tAX/M VM *Otf? rCA*P£RJiTVf?£ 
 
 A? 
 
 2f ?S 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 nun 
 
 ~\/VO KA//V. 
 
 Diagram showing the temperature of the undried corn in car No. 75197 and of ilio dried damaged 
 
 corn in car No. G7031; the daily maximum air temperature; and the weather recor I from April 27 to 
 June :s. 1909, whlli " elevator yards. 
 
 ( )n Mas _'"i 1 hi- corn was unloaded, weighed, handled over five eleva- 
 tor-, reweighed, screened, weighed a third time, and returned t<> the 
 car for further obsen ation. When the emu was returned to the car 
 the second time (May 25 • the temperature was 7'l 1''.. approximately 
 the same a- the temperature of the air at the time the corn was 
 handled. On .lime :;. 9 days later, the corn in thi- car was again hot. 
 the maximum temperature being L12 1''.. showing that hoi corn i- 
 iiut made safe for shipment when cooled -imply by handling. 
 
 Figure •"> shows the changes in temperature in both the car of 
 undried corn and the car of dried damaged corn while on the track 
 
 [Cil 
 

 ^^^^_ 
 
 
 
 < 
 
 (D 
 
 Q 
 
 
 O 
 
 ^^^flj 
 
 — 
 
 gn 
 
 Li. 
 
 LL 
 
 <M 
 
 O 
 
 O) 
 
 
 ^^^=C0 
 
 > 
 
 o 
 
 h- 
 
 (fl 
 
 ^^^^ M ^^ 
 
 X 
 
 = <o 
 
 LU 
 
 ^^(^ 
 
 > 
 
 -- - - T— 
 
 z 
 
 
 3 
 
 
 
 ^^^^= 
 
 
 ^^^^_ 
 
 
 
 
 
 
 12 THE DETERIORATION OF CORN IN STORAGE. 
 
 from April 27 to May 25 and from May 25 to June 3, together with the 
 daily maximum air temperature and the weather record for the same 
 period. The diagram also shows that only the corn near the surface 
 was influenced by the temperature of the outside air. 
 
 LOSS EN MOISTURE AND SHRINKAGE. 
 
 When the undried corn from the bin was first loaded into car No. 
 75197, on April 27, the average moisture content was 17.47 per cent. 
 On May 25, when the maximum temperature of the corn was 122° F., 
 the average moisture content of the surface corn was 13.55 per cent. 
 Samples taken from 5 inches below the surface showed a moisture 
 content of 17 per cent. The highest moisture content found was 
 17.5 percent, in samples taken at the point where the temperature 
 was 122° F. 
 
 The shrinkage in weight in the layer of corn at the surface, based on 
 the reduction in moisture of 3.92 per cent, was 4.53 per cent. On 
 May 25 this corn was unloaded and reweighed by the weighman of 
 the Chamber of Commerce on the scales regularly used at the ele- 
 vator. The loss in weight in the loading and unloading and through 
 evaporation while in the car from April 27 to May 25 was 367 pounds, 
 or 0.728 of 1 per cent. This corn was then handled over five elevators, 
 screened, weighed, and reloaded. In this handling and reloading 
 the moisture content was reduced to 16.55 per cent, or 0.92 of 1 per 
 cent less than when the corn was first loaded into the car on April 
 27, which is equivalent to a loss in weight of 1.1 per cent due to the 
 evaporation of moisture while in the car and in the handling of the 
 hot corn in the elevator. On June 3, this car of corn, cooled by 
 handling, was again hot, the temperature having increased from 73° F. 
 to 112° F. from May 25 to June 3. The average moisture content of 
 the surface corn was only 13.95 per cent, as compared with 16.55 per 
 cent when reloaded, a reduction in moisture of 2.6 percent in 9 days. 
 
 The low moisture content of the surface corn showed that water 
 was being lost by evaporation and that this evaporation is quite 
 rapid when the temperature of the corn is relatively high. It must 
 be remembered, however, that this car was opened frequently and 
 the com on the surface more or less disturbed in the securing of sam- 
 ples, in reading temperatures, etc., so that the same results might 
 not apply in the same degree to corn in transit where the cars are 
 unopened from point of shipment to destination. 
 
 Approved: 
 
 James Wilson, 
 
 Secretary of Agriculture. 
 
 Washington, I). C, November 5, 1009. 
 
 | Cir. 43] 
 
 o