THR 
T H R 
795 T H R 
diminished third in airs, but it is never us«d 
in harmony. 
The consonant thirds are the spirit of har- 
mony, particularly the major third, which is 
sonorous'and brilliant ; the minor third is 
more tender, and even pathetic ; a difference 
of character from which skilful composers 
derive some of the beat and most poignant 
effects. 
The old French theorists had almost as 
severe laws respecting the thirds as we now 
observe in regard to fifths and eighths, it 
was by them forbidden to have two in imme- 
diate saccession even of different kinds, par- 
ticularly in the same direction. 
THIRTEENTH, in music, an interval 
forming the octave of the sixth, or the sixth 
of the octave. It contains twelve diatonic 
degrees, i. e. thirteen sounds. 
THOA, a genus of the monoecia polyan- 
dria class and order of plants. There is no 
calyx or corolla; the male stamina are nu- 
merous; fern, germ, two ; stigma three or 
four-cleft; seed in a brittle she'll, covered 
with a bristly nect. There is one species. 
THORACIC, a term applied to an order 
of fishes in the Linnean system ; the charac- 
ter of this order of fishes is, that they have 
bony gills, and ventral fins placed directly 
under the thorax. Of this order there are 
2 1 genera, viz. the 
Cepola, Plenronectes, Trachychthys, 
Echineis, Chahodon, Gasterosteus, 
Corvphsena, Sparus, Scomber, 
Gobius, Scarus, Centrogaster, 
Cottas, Labrus, Mul lus, 
Scorpiena, Sciaena, Trigla 
Zeus, Perea, Lonchiurus. 
Thoracic duct. See Anatomy. 
THORAX. See Anatomy. 
The thorax of insects is the back part of 
the breast. See Entomology. 
THORNBACK. See Raia. 
THOUINIA, a genus of plants of the 
class diandria, and order monogyuia. The 
corolla is quadripetalous, the calyx quadri- 
partite, and the anlherae sessile. There is 
®nly 01 'ie species, a tree of Madagascar. 
THRASHING, or Threshing, in 
agriculture, the art of beating the corn out 
of the ears. 
Thrashing-machines. The thrashing 
of corn by means of machinery, has been 
long in use in the northern districts of the 
kingdom, and mills of this sort are now be- 
coming general in most parts of the country ; 
and upon arable farms of considerable extent 
they cannot but be highly advantageous, as 
they save much labour and expence. I 11 the 
making of those machines, attention should 
•always be had to the size of the farms, or 
or rather the quantity of grain that may be 
grown 011 them, and the mill proportioned 
accordingly. They are mostly constructed 
on the principles of the flax-mill, and are 
moved either by water or horses, the first by 
far the best method where it can be had ; 
the grain by these machines being, in a man- 
ner, swingled out ot the ears by means of 
beaters which are attached to a cylinder that 
moves with very great velocity. Since the 
introduction of these machines, many im- 
provements have been made on them ; a 
screen has been added for the grain to pass 
through into a winnowing-machine, and a 
circular rake to semove the straw from it ; as 
before this addition the straw was forced out 
from the beater upon the upper barn-floor, 
and required much time and labour in shak- 
ing and putting into order, which by this 
contrivance is saved. I 11 working these mills, 
four persons are commonly necessary ; one 
takes the slieaf from the stack, another places 
it ready for the third who is to feed the mill, 
and the fourth removes the straw to prevent 
its collecting in too large a quantity. It has 
been objected to these machines, that they do 
not thrash some sorts of grain clean ; this has 
been particularly the case with barley. It is, 
however, observed by an intelligent writer, 
that the circumstance on which the good 
thrashing of this kind of grain depends, is 
the iron covering under which the beating- 
wheel, having six beaters, moves : in some 
machines this is fixed, while the beating-wheel 
is capable of being raised or depressed at 
pleasure ; but a recent improvement is, to 
render the iron roof moveable, and the wheel 
fixed ; and the iron is placed so near to the 
beaters that the grain is rubbed, as well as 
stricken out of the ear. In some machines 
of this sort, the beaters are a little rounded ; 
but it is probably a better practice to have 
them of the common flat form. 
In some large mills of this kind the rollers 
take iii about three hundred inches of grain 
in a minute. The medium length of the 
straw being estimated at about thirty inches, 
and supposing half a sheaf to be introduced 
into the machine at a time, the whole sheaf 
will be equal to sixty inches, and the ma- 
chine, when supplied with a middling quan- 
tity of water, will thrash five sheaves in a 
minute. But in respect to the performance 
of . these mills much must depend on the at- 
tention with which they are fed, as a small 
neglect in this point will make a very con- 
siderable difference in the quantity of w r ork 
done. 
An excellent description of a mill of this 
nature is given in a late publication, in which 
it is remarked, that in such mills five people 
are commonly necessary to keep the work 
going on without embarrassment; but that 
this depends greatly on the construction of 
the machines, some of them being so con- 
trived, that the work can be performed with 
much fewer hands. The manner in which 
j these people are employed is this : One finds 
constant work in carrying the sheaves to the 
man who feeds or puts the unthrashed corn 
into the machine, and in loosing the bands ; 
another is required to feed the machine ; a 
| third to carry off the straw ; the fourth to 
attend the fanners, and lay aside the cleaned 
grain ; and a fifth, where horses are made 
use of, to take care that they go regularly ; 
and thus by means of five men and four 
horses they will thrash at the rate of five 
quarters in the hour on a medium, and when 
the crop is rich, and easily thrashed, consider- 
ably more : consequently if a thrashing-mill 
was to be employed for a whole day, or nine 
hours, it would thrash forty-five quarters ; 
but in that case it would be necessary to 
employ two sets of horses. The expence is 
calculated in this planner : 
<£. s. d. 
Hire of eight horses, at 2s. 6d . 
each per day, - 16 0 
Five men’s wages, at 1$. 6d, each, 0 7 6 
«£ 1 7 6 
k 
In this account the hire of the men and 
horses is, it is conceived, charged at the 
lowest rate, and that the expence of thrash- 
ing forty-five quarters of grain would cost 
ab'out l/. 7s. 6 d. or about 7 d. each quar- 
ter. But that taking the average expence 1 ', J 
of thrashing forty-five quarters of grain with 
the flail, throughout the whole kingdom, in-| 
eluding an equal proportion of all kinds, it I 
cannot be, it is supposed, estimated at less J 
than 31. 7s. (kl. or 1,?. 6ci. each quarter, |j 
which makes a difference of about 1 1 d. each* j 
quarter. It is also farther observed, that J 
since the introduction of these mills, the I 
grain is thrashed by the ordinary servants on I 
the farm, and without in any material de-y 
gree obstructing the operations in the field ; l 
fanners in general employing their men and d 
horses in this business in bad weather, when® 
other operations cannot be carried on. 
The whole expence of constructing a 
thrashing-mill, including the building of the! 
shed for covering the great wheel, does not, j 
in almost any case, exceed 100/. The or- 
dinary annual repairs may, one year with 
another, amount to 5/., which added to the 
interest of the prime cost, makes the yearly 
expence 10/. ; a sum for which any quantity# 
of grain, however great, that may be supposJ 
ed to grow on one farm, can be thrashed,® 
and that too in a manner much superior to 
what can be done by manual labour. The* 
expence either of erecting these machines, or^ 
of keeping them afterwards in repair, must! 
be considered by every intelligent occupier! 
of a corn-farm as a secondary object, when! 
compared with the advantages that are de-1 
rived from them ; such as the performing of 
the operation at less than half the ordinary j 
price, and affording the farmer the means of 
securing his grain from being embezzled ;| 
besides, the saving, in regard to superior cleau| 
thrashing, as has been now well ascertained,! 
is not only more than the annual expence of] 
repairs, but so great as, on a farm of consider- J 
abie extent, to reimburse the farmer for the 1 
whole of his expenditure in the course of a 
few years. Considering, therefore the in- 
creasing scarcity of labourers, and the recent 
great advance in the rate of labour in all the : 
better cultivated parts of the kingdom, the 
introduction of thrashing-mills into coni mom 
use cannot but be highly beneficial. 
There is, however, one difficulty in the 
introduction of thrashing-mills into the south- 
ern parts of the kingdom, which arises from, 
the manner of harvesting all kinds of grain J 
except wheat, which cannot probably bel 
easily removed ; as the corn, in order to bel 
clean thrashed, should be put into the machine! 
as straight and regular as possible. For 
while the sheaves, after being loosened and 
spread on the board, so as to be easily taken 
in by the feeding rollers, are passing between 
them, they keep the straw steady, by which] 
means the strokes of the beaters or scutchers! 
operate with more force and effect in sepa- 
rating the grain from the ears; whereas, if- 
the unthrashed corn goes in sideways or irre- : ) 
gularly, the thrashers can have but little- 
power upon it. This would no doubt fre- 
quently happen in thrashing corn which has 
been mowed with the scythe, and which is 
harvested in every respect like hay ; so that 
unless the unthrashed grain is put into the 
mill in small quantities, it is almost impossible 
