Pe SS RS ee 
DUST EXPLOSIONS IN GRAIN SEPARATORS. 7 
by the investigators as indicating incendiary origin was very small 
as compared with that advanced by local men. 
PERCENTAGE OF SMUTTED HEADS. 
The percentage of smut present in the wheat crop was determined 
in each case by taking a sample of a known number of heads and 
separating it into two parts, one part consisting of those heads 
which were not affected by smut, the other part of those heads which 
were affected. The proportion of smutted heads to the whole number 
of heads in the sample gave the percentage of smutted heads present 
in the crop. 
Of 112 explosions nearly all occurred during the threshing of 
grain which contained from 1 to 35 per cent of smutted heads; the 
average percentage in 108 explosions was 15. There were only three 
explosions in fields reported to contain no smut. 
Percentage of No. of ex- Percentage of No. of ex- 
smutted heads. plosions. smutted heads. plosions. 
KO SET ee Sole tOne OPO Qn: temas eel eeen nes: 20 
Wess= thalk at sere COM se 2 — Sa 2 Pale stOrco Pere COME. ase. 4 ie 6 aie De, 8 
AtOeO Pel 2COM betes eww re 195} 325; to:; SO" per cent S22 aa ic 
Dato TOR per Conia akin tens bo ZC a eSOntLOgoo Percent. sc sss sie a 
IGstomieper cent eS ees ALES EIN Ot O We ee es Pee 4 
SIZE OF MACHINE. 
The results of the investigation in relation to the size of machines 
affected indicate that explosions occurred in all kinds and types of 
machines, irrespective of size. 
SPEED OF CYLINDER. 
The fact that many explosions occurred while the separator was 
being operated at the cylinder speed recommended by the manufac- 
turers indicates that operation of the machine at excessive speed is 
not essential to produce an explosion. 
POWER USED. 
The kind of power used in operating the machine was of special 
importance, since one of the early suggestions as to cause was that 
engine sparks were responsible. It was found that explosions and 
fires tcok place in gasoline-driven as well as in steam-driven outfits, 
and that the cause of ignition was within the machine itself and not 
external. In 113 machines investigated the power used was as ~ 
follows: 
CaCO ITC ts ee ee eee ne 1So Pe ETECERTE IO LON eres nee ye ce eee al 
ASE TT Rete ce OS)! TEROR SEG Ss ee FOF SPEEA CEPT EAT oS aft 
As the largest number of machines in the territory were operated 
by steam power the figures just given do not indicate that steam- 
driven outfits are more subject to explosions than are other types. 
They do, however, discount the theory that explosions occurred only 
in machines operated by steam power. 
