A PAPER BY
B. A. DOBSON, C.E., M.I.M.E.,
CHEVALIER DE LA LEGION D'HONNEUR. # •♦
^ • 1895 • ^
■.X:i''i'.>^ i^'fTv :^'i
COPYRIGHTJ. [ALL RIGHTS RESERVED.
A PAPER BY
B. A. DOBSON, C.E., M.I.M.E.,
CHEVALIER DE LA LEGION D'HONNEUR.
(author of "the principles of carding cotton,'"
" SOME difficulties IN COTTON SPINNING," &C., &C.)
READ AT THE
BOLTON TECHNICAL SCHOOL.
before THE TECHNICAL INSTRUCTION COMMITTEES, MASTER COTTON SPINNERS, MILL
MANAGERS TECHNICAL ASSOCIATION, AND MANAGERS AND OVERLOOKERS
ASSOCIATION OF BOLTON AND DISTRICT, AND COMMUNICATED TO THE
NEW ENGLAND COTTON MANUFACTURERS ASSOCIATION,
7th DECEMBER, 1894.
G. S. HEATON, PRINTER, VICTORIA WORKS, BOWKER'S ROW,
Op. Cetl ,
What I intended originally to be a few Notes on
the subject of Humidity in Cotton Spinning has, by
force of circumstances, expanded into a fairly sized
booklet. Again, whereas, at first, no illustrations were
comtemplated, I have found it necessary, for the pur-
pose of explanation, to include several. I trust the
result may be of practical benefit to the trade con-
cerned, if not directly by the information I have given,
at least indirectly by the criticism it may induce.
. B. A. DOBSON.
HE general interest taken in this subject, judging
by the number of papers lately read and the
discussions upon them, only points to the fact that it is
a subject, the scientific study of which has been some-
We in this part of England, in Lancashire, have too
long considered that we are specially favoured by nature
in some very great degree, and that outside this county
fine cotton spinning has been next to an impossibility.
This raises the question of climatic suitability ; and I
propose to consider, shortly, from a practical point of
view, those conditions which concern the subject, and
the means of modifying unfavourable circumstances, in
order to produce better results in the processes of manu-
Some two years ago, I caused to be made an elaborate
system of observations in mills spinning difi'erent numbers,
with a view of ascertaining what degree of comparative
similarity in atmospheric conditions could be found in
mills spinning much the same numbers for the same
market, in trade competition. I discovered, to my
surprise, that this important question was very much
neglected from, as I have just said, a scientific point
of view. There are many mills where there are no
instruments for ascertaining, exactly, the climatic con-
ditions — in some other establishments, however, the use
of them forms part of the duty of the staff and of the
daily routine. I found, further, that where science had
not been consulted the natural resource of the work-
people exhibited itself in the most practical and simple
way. Thus, in weather when a dry east wind and low
temperature produced an atmosphere unfavourable for
spinning, that friend of the cotton spinner, the "degging
can," came into legitimate and successful operation.
The climate most resembling that of Lancashire is
the flat plain of Lower Flanders, known now as the
Departement du Nord, in which is situated the wealthy,
important, and thriving town of Lille.
The cotton spinning industry in this district is
almost as old as that of this country. And I may say,
as regards fine spinning, it has been carried as far
towards perfection as it is here ; and that so far as
results are concerned, the people have little to learn
from us. On the other hand, the fact of the mills
being comparatively small, with a limited number of
spindles to each establishment, causes an uneconomical
result in cost of production which, in spite of duties,
permits of competition from our own country.
OLD COTTON MILLS IN LILLE.
It may be said, broadly, that the mills constructed
some seventy or more years ago were built exactly on the
same plan as the mills erected in the city of Manchester
and district at the same date, or previously, allowing
for the peculiarity of construction obtaining in the two
Thus the buildings had thick walls and small win-
dows, and the ceilings were lower. The entrance to
each spinning room was from the staircase, well protected
below from sudden incursions of cold winds; and the
floors, and woodwork generally, were saturated with many
years' accumulation of oil. This circumstance alone is of
importance, inasmuch as the oil would form a sort of
protection against sudden changes of temperature of the
floor or walls or ceilings. Again, the small size of the
rooms, and the little opportunity for the entrance of
extraneous air, made the problem of maintaining an
equable temperature one easier to solve.
It is within my knowledge that a firm in this county
of Lancashire, having a very ancient building constructed
according to the foregoing particulars, and having a
modern mill with increased floor space, window space,
and height of ceiling, have found it impossible to spin the
same numbers with equal results, the yarn from the old
mill invariably being smoother. This will form the text
upon which I am proceeding.
EELATION OF HEAT TO FIBEE.
It may be well to state at this point — although I
presume most persons in the business of cotton spinning
know it as well or better than I do myself — the reasons
why cotton will spin better at one time than another.
There are two causes for this, one of which hinges upon
the peculiarity of the structure of the cotton fibre. If
the cotton fibre be cold and dry it is what is termed
''harsh ;" and a spinner who is accustomed to pull cotton
can instinctively make allowance for the degree of dryness
of that cotton he is testing. When the fibre is cold and
dry the waxy envelope of the fibre is congealed ; and,
consequently, there is some resistance of the fibre to the
processes of manufacturing, known as "drawing" and
"spinning." Although I have stated this very simply, I
believe I have named all the facts as regards the relation
of heat, ;per se, in its effect upon the fibre.
Now if this were all, it would be enough if heated
air were supplied in sufficient temperature to maintain
the fibre in a supple condition. But here comes in
another factor in the problem. If the fibre be hot and
dry it is peculiarly susceptible to the influence of
electricity. This is a phenomenon often most difficult
to deal with.
EFFECTS OF ELECTEICITY.
From first to last, in a cotton spinning mill, free
electricity interferes in each operation with the process
of manufacture. Opener, scutcher, card, drawframe,
flyframe, and mule or throstle— if the conditions are
such that electricity has perfect hberty, the result must
show inferiority of the product. I have seen mills of
recent construction, especially fireproof mills, where
every shaft, column, and beam in the fabric of the mill
were charged with electricity to such a degree that cotton
fibre stood out from the ironwork to the distance of at
least three inches— radially to the centre of electric
attraction. An infalhble and ready proof of the existence
of the electricity is in carefully observing the ironwork of
the machines. Of course, in all mills, there is a certain
amount of loose fibre called "fly" floating in the air.
If it is found on any of the ironwork standing straight up
from the surface hke the bristles of a brush, there is no
necessity for further argument— the presence of electricity
is declared. Very often this comes from the slipping
friction of the driving straps and is conveyed, say, from
the driving shaft pulley to the pulley of the machine ;
charging the body of metal with latent electricity, which,
in its turn, affects every fibre in its passage.
I have tried, occasionally, to extract the electricity
from the machine, with very considerable success. Thus
with a copper wire attached to any part of ironwork
forming what is termed "earth," by placing the other
end of the wire near the inside of the leading strap, the
electricity was taken from the strap and prevented from
going into the machine itself. On a revolving flat
carding engine, which was so charged by electricity
that the fly on the flats stood straight up from the wires.
I have been able, by the movement of the wire, to make
this fibre rise and fall at will. In combing machines,
where it is desired to comb as much width of lap as
may be practicable for the length of the roller, this
action of electricity is very marked, and becomes of
A very large and eminent spinning firm in America
had a number of combers made to comb the same width
of lap as they had seen successfully combed in a mill in
this country ; but after a year's trial they found so much
difficulty and so much waste made that they went to the
extreme course of sending their manager to England
to see, again, the machines which had served as a sample
for the giviug of the order ; to ascertain whether they did
work as satisfactorily as the firm had supposed. They
found that the machines did so ; and the firm were
forced to the conclusion that they would have to comb
a lap one inch narrower than we can do in Lancashire,
on account of the effect of the latent electricity upon
the loose fibres of cotton.
The action is to separate the fibres. Fibres under
this influence cannot be brought together ; consequently,
more room is required for the operation. I have, myself,
seen not once, but several times, the cotton issuing from
a drawframe roller refuse to pass down the funnel to the
coiler, and float in the air like a snake right over the
calender rollers on to the floor.
What is true of the card, comber, and drawframe,
is also true of the flyframes and spinning machines.
But in the spinning machines the presence of electricity
is shown by accumulation of fly on the working parts —
the rough, furry, character of the thread made, and
its brittleness and liability to snap. As showing the
extraordinary effects that can be produced by this, I know
of a mill which, when starting its new machinery, had
several breakdowns of the openers and scutchers ; but,
more particularly scutchers, after stopping the machine
and restarting. A little observation showed that in each
case a huge parcel of cotton of considerable density had
been carried to the metallic cages, and, by over pressure,
owing to the great thickness, had caused breakages of the
wheels. A little examination showed that, after running
some time, the whole of the interior of the beaters, from
the centre shaft to the blade of the beater, contained a
dense block of cotton, which filled in the space as
symetrically as if it had been made purposely in wood.
After a certain time, when the machine had been
stopped long enough to allow the electricity to be dis-
engaged, these pieces fell as the machine restarted and
were thrown by centrifugal force into the cages.
I examined these extraordinary blocks of cotton and
found that the fibres were ranged parallel end to end in
line from the centre of the beater shaft to the inside
surface of the beater blade. In this case, the objection-
able phenomenon disappeared as soon as the room had
been heated, and the straps driving the machine had been
thoroughly well moistened with composition. The fact
was the machines were at first thoroughly insulated from
the floor ; the driving strap slipping on the line shaft
pulley was acting as a sort of electric machine and
charging, by means of the strap, the opening or scutching
In America, this has been considered of such
importance that in many mills there are special arrange-
ments for preventing conduction of electricity from the
driving straps to the machines.
Mr. Buchanan saj-s in the Phil. Mag., U.S., Yol. I.,
page 581, that in a "factory at Glasgow the accumulation
of electricity in one room in particular, in which was a
large cast iron lathe, shears, and other machinery driven
with great velocity by belts was so great that it was
necessary, in order to protect the workmen from
unpleasant shocks, to connect the machinery with
copper wire with the iron columns of the buildings, and
that when a break in the wire was made at a quarter of
an inch the succession of sparks was very rapid. The
electricity was positive."
Thus in the case of the scutchers I have named the
phenomenon ceased when the slipping of the strap was
prevented by the composition which, at the same time,
acted as a non-conductor, preventing the surface of the
leather from touching the surface of the iron drum.
In connection with this subject of electricity and its
practical effect upon spinning, I would refer to a pamphlet
by Mr. Harry S. Chase, read at the Massachusetts Insti-
tute of Technology, in 1883, in which the phenomenon
occasioned by electricity in spinning white cotton, dyed
cotton, and natural and dyed wools, is very fully dealt
with ; and in which the author describes different
methods by which electricity can be generated in a
spinning mill and communicated to the material under
operation ; as, also, the best method of preventing or
removing the electricity. It would seem from the result
of Mr. Chase's investigaMons that the principal cause is
the friction occasioned by the sKp and pressure of the
strap on the driving pulley, in which, as in all electrical
phenomena, the surface of the strap will produce one
electricity and the pulley another. In every case tested,
the electricity developed was negative in the belt and
positive in the pulley. Above and beyond the difficulty
occasioned by this occurrence, there is a greater one in
that the stock of material may be charged with electricity
generated elsewhere, and communicated by beams, pillars,
gas pipes, or bolts. Cases have been known where the
cotton in the mixing room was severely charged from the
bolt heads of the hangers driving the machinery pulley.
It may be said, en passant, that material, either cotton or
wool, charged with electricity is exceedingly difficult to
discharge ; and only time and a kindly atmosphere can
effectually perform this. The author also mentions the
effect of steam being allowed to flow into rooms,
principally weaving sheds, for humidifying purposes, in
order that "electricity may be killed ;" and where it was
found that the very opposite effect was produced, from
the fact that steam was developing the same quahty of
electricity as that existing in the room. The writer
completes his paper by discussing the question of moisture
in the air and the extent of steam admitted, further
pointing out that a too great proportion of moisture would
have an injurious effect upon the work, as the springs and
elasticity of the fibre is weakened. He then makes some
general remarks upon the observations of the hygrometer,
and draws a conclusion with which I must strongly
disagree ; one in wln'ch he states that the humidity for
good working is less than expected, and he places the
limitation between bad and good work at from 30 to 40
per cent, of saturation. This I think will, further on, be
seen to be quite outside the mark ; and Mr. Cliase winds
up with an assertion I reproduce literally: "A careful
consideration of these statements will satisfactorily prove,
I think, that the whole question of escaping from electri-
cal trouble will be found in the matter of relative
humidity. If there is sufficient moisture in the
atmosphere, there is no trouble ; if there is not sufficient
moisture, electricity always appears. The question is
resolved into deciding on the best and most satisfactory
method of getting the moisture into the mills and this
brings in, as all improvements ultimately do, the
consideration of the relative cost of the annoyances and
HYGKOMETEICAL CONDITIONS OF THE
Now the author might have gone even further than
he has done, and pointed out the impossibility of produc-
ing good yarns in either cotton or wool, if the hygro-
metrical conditions of the atmosphere were unfavour-
able ; the reason being, as I have stated before, that the
effect of the existence of the free or latent electricity is to
produce mutual repulsion in the fibres being dealt with ;
and therefore in the processes of spinning and twisting
the end of the fibre not immediately under control has a
tendency to radiate from the centre of the body of fibres
in action, and to produce rough, or what is familiarly
known as ''oozy" yarn. I may say that the only
effective method of avoiding the inconveniences previously
alluded to is by moistening the air to such an extent that
it will prove a sufficiently good conductor to disengage
the electricity existing in the fibres.
In countries where there is a very wide range of
temperature and where the climate at certain seasons is
excessively dry, these differences are more serious than in
countries where the contrary obtains ; although even in
this climate of Lancashire the difference between a west
wind and an east wind often makes a margin of 7 to 8^-
per cent, in the production of a weaving shed.
Boston is the chief town of Massachusetts and is, to a
certain extent, a centre of manufacturing, and may almost
be termed the American Manchester. The mills are not
immediately in the town. They are at short distances
round and are in practically much the same climate as
the town of Boston itself. What difference there is, is
perhaps rather against the manufacturing districts, as
most of them are inland from Boston, and, consequently,
there is slightly less humidity than in the neighbourhood
of the coast line, where the vicinity of the ocean tends to
make the climate equable.
COMPAKISONS OF DISTRICTS.
In making a comparison between one district and
another, as regards its capabilities for manufacture there
are several points wdiich must be carefully weighed in all
cases ; the first being tbe question of mean temperature,
the second the extreme range of temperature, and the
third the natural percentage of humidity under the
varying temperatures. I append a table of statistics with
regard to the foregoing conditions and will endeavour to
deduce the values, for the purpose of manufacturing —
say cotton spinning, in each case. I have taken twelve
parts of the world— the 10th, 11th and 12th being, res-
pectively, Boston (Mass.), Bolton, Lancashire, and the
district near Lille. I will proceed to show why, and to
what degree, each is favoured by its climatic peculiarities
for this particular industry. I have given in each case
the maximum and minimum temperature and the mean
maximum and minimum of humidity, and, also, the cal-
culated annual mean. The latter is of little value as a
factor in the problem, as, of course, extremes of condi-
tions of humidity would not affect the calculated mean ;
although one extreme, or the other, or both, might
be very prejudicial to the working of the fibre. And I
may state, as a principle, that the less the range of tem-
perature, and the more regular the degree of humidity,
the better the conditions. Thus, for instance, take the
contrast between Boston and Bolton. I find the highest
monthly mean humidity in Boston to be 85 per cent.,
against Bolton 93-1 per cent. ; the lowest monthly mean
66 per cent., against our 69 per cent. Moreover,
comparing the annual mean humidity, Boston 74*5 per
cent., and Bolton 81 '9 per cent., the contrast shows
an immense advantage for cotton spinning here. Again,
take the range of temperature — in Bolton it is 62*8 deg.,
whilst in Boston it is 92 deg.
When the temperature in Boston is minus 1 degree,
the amount of vapour in suspension would be practically
nil, or about half a grain per cubic foot ; consequently,
when the air is heated sufficiently to allow of spinning
operations, it would be absolutely necessary, even for
considerations of health alone, to impart an artificial
humidity. The conditions of the district near Lille will
be seen ; they resemble closely those of Bolton.
On the following page will be found the tabulated
statement referred to, with criticisms on the adaptability
of the various climates for spinning.
^.^ ce .
g 3! 03 .
2 s^ > a -"
<D -g 60 >•
Jp •ran 01
WEIGHT OF AQUEOUS VAPOUR per CUBIC FOOT
i — h90<-^wfl>»3a»o-Nw?oi5'353<
DIAGRAM OF SATURATION
2 1^ \
^ "I T
5 , -^
POIDS deVAPEUR par METRE CUBE
INFLUENCE OF VAPOUR.
That those who have not had au opportunity of study-
ing the question of the principles involved in evaporation
and in suspended vapour may do so, I append a table
diagram on page 13 from which may be seen, at a glance,
the weight of vapour per cubic foot, or per cubic metre,
which constitutes what is known as saturation ; satura-
tion, of course, meaning that each particle of air is
supporting as much weight of fluid in its minute globular
form as it is capable of doing. This is known as the
elastic force of aqueous vapour. The table is read from
the perpendicular column on the left to find the number
of grains per cubic foot, and along the upper column to
find the temperature on the Fahrenheit scale. On the
right hand are the number of gramms per cubic metre, and
on the bottom the scale of temperature on the centigrade
scale. Thus, by reading up from the bottom and from the
left, the weight of aqueous vapour required to saturate a
cubic foot at any temperature in the scale can be readily
seen, and the same by reading from the right hand side
and from the bottom for the metric system. It will be
seen that, as the temperature rises, the air is capable of
containing more and more moisture. Thus, at 212
degrees Fahr., the air would be developing steam, and
that at 40 degrees below zero, Fahr., the air is not capable
of supporting vapour.
This, of course, accounts for the bright crisp air in
excessively cold weather, and for the muggy damp air
occasionally met with in the dog days. It accounts, like-
wise, for the phenomenon met with in the cold coun-
tries, such as Canada or Russia, where, on a bright sun-
light day, with a blue sky, finely powdered snow falls in
quantity ; the fact being that a stratum of air which, by
its greater temperature has absorbed moisture, elsewhere,
is suddenly congealed and obliged to part with that
portion of vapour over and above its proper quantity
for its temperature. Further, it is responsible' for the
heavy dew in hot weather, where, when the air has been
heated all day, and the moisture of the earth and the
surface of adjacent water has been evaporated by the
heat of the sun, and taken into suspension by the heated
air, at sundown, the difference of temperature, owing to
terrestrial radiation, forces the air to part with its excess
of moisture. Thus, as I have practically proved, it is
possible in the tropics, to become wet through in a two
miles' walk after 9 o'clock in the evening, the moisture
formed on the clothing being visible and perceptible to
In the proceedings of the Koyal Meteorological
Society of January, 1893, under the heading of " Corres-
pondence and Notes, " there is a statement referred to by
Mr. F. E. Saunders in the "Bulletin of the New Eng-
land Weather Service for September, 1892," in which
he states : —
"It is a well-known fact that the temperature has
quite an important bearing upon cotton fibres during
the manipulation from the bale to the cloth -room.
This must be evident to the most casual observer when
we consider the fact that cotton is grown in a warm
climate, surrounded by a mean temperature of 70
deg. and then transmitted to a climate that is subject
to sudden atmospheric changes, many of them being of
low temperature and with an atmosphere divested of
" Cotton fibres are very susceptible to any atmos-
pheric change ; that is to say, they will take on or throw
of! dampness very readily, consequently any material
change of temperature and humidity will affect the
successful working of the fibre. In order for cotton
to work well in the first processes of manipulation, the
dry bulb thermometer of the common psycbrometer
should stand at 78 deg., and the wet bulb at 66 deg.,
which would make the dew point 58 deg., and the relative
humidity 52 per cent. This would give 5'371 grains of
water vapour per cubic foot of air. Cotton fibres, with
this condition of atmosphere, will very readily assimilate
and draw even. During very many of the atmospheric
changes that are constantly taking place it is found quite
impossible to bold the cotton fibres well in hand. This is
more noticeable when dry atmosphere prevails with a dry
west-north-west wind blowing for twenty-four or thirty-
six hours. It is frequently the case, where these changes
take place, that the amount of water vapour in a cubic
foot of air will drop as low as 4*29 grains. When these
conditions occur the electrical currents of air seriously
interfere with the workings of cotton fibres. Electricity
causes the fibres to separate, and much more waste is
made. Very many of the cotton mills in New England
are not supplied with moistening apparatus.*"
HUMIDITY AND TEMPERATUEE.
It will be seen from the foregoing, that tbe question
of humidity is intimately allied with that of temperature;
and in manufactories it is first necessary to fix the
temperature at which the workroom shall be kept and
then to make such arrangements that this air may be
supplied with the amount of moisture sufficient to make
the air soft enough for the comfort of the workpeople and
* The use of hygrometers to indicate the eonditiuii of uliuosphere in Kpinuing mills was rendered
couipulsoiy iu Eiiglaud by the Cottou Cloth I'aetoiits Act, lt*iU.
the conditioning of the fibre, and to render the atmos-
phere a sufficiently good conductor to subtract the
extraneous and superfluous electricity. The following
table gives the maximum amount of humidity allowed
by the Act of Parliament referred to. It will be noticed
that the vapour allowed is considerably in excess of any
of the undermentioned observations : —
COTTON CLOTH FACTORIES ACT, 1889.
Maximum limits of Humidity of the Atmosphere at given Temperatuees.
foot of Air.
foot of Air.
It would be well to here show what inquiries arid
investigations I have made with a view of ascertaining
the exact working conditions obtaining in the district of
Bolton, where our chmate is supposed to be specially
favourable for the spinning of super-extra quality of yarn.
And I may say, in passing, it is a fact that no district
has spun, so far, the special numbers and qualities of
Bolton yarns to as good, or certainly not to better,
advantage than is done here.
Knowing, as I did, personally, the conditions ex-
isting in a large number of manufactories, I could tell
where and how to find the information that specially
interested me. Therefore it was a more simple matter
than would at first appear to find the typical examples
and make the necessary comparisons. My examples
have covered fifteen different mills, of which two were
engaged in spinniug wool. The numbers spun in these
mills ranged from 40's to 160's. The mill spinning 160's
had been arranged for much finer numbers, but, owing
to the vagaries of the market, had spun considerably
coarser numbers. Most of the mills were mule spinning;
but one was a ring spinning mill, and one of the woollen
mills was cap frame and the other mule spinning. I am
glad to render tribute to the alacrity with which my
request for permission to make these investigations was
accorded in all cases. The only stipulation was that I
would keep to myself the names of the firms concerned.
This, I need hardly say, T have strictly complied with.
ADVANTAGES OF HYGROMETERS.
As will be seen from the foot- note to Mr. Saunders'
remarks, the use of hygrometrical thermometers under the
Cotton Cloth Factories Act, 1889, is compulsory. But
the provisions do not extend to spinning mills. It is a
great misfortune that it should not be wholly compulsory,
because it would result in a better understanding of the
most favourable conditions for manufacture. In every
case where I have examined the instruments I found the
same radical defect. That is to say, the wet bulb and its
well are so near the dry bulb as to affect the truth of the
reductions of observation from 8 to 13 per cent, in the
amounts calculated as percentage of humidity. Thus, in
most cases, the thermometers were only 2^ inches apart,
and one I noticed in particular only li inches. Now the
thermometers should not be less than 4 inches apart, and
the well of the wet bulb should be at least 5 inches from the
dry bulb. Even then, if observations are carefully noted,
it will be found there is a difference of from 1 to li per
cent, in apparent humidity between an observation in
which the dry bulb is frequently wiped with a dry cloth
and that in which it is left to acquire the moisture from
the wet bnlb, even at the distance of 4 inches. Thus in
twenty-one readings under average circumstances, after
allowing for corrections for what are known as " certified
index errors," the standard instrument showed 83-1 deg.,
as against the mill instrument 777, and the standard
instrument 95-2 against the other 89 deg. By carefully
working out the figures, say of the first observation,
it will prove, after the proper correction, a relative
humidity to saturation, of 37 per cent, by the standard
instrument and 55 per cent by the mill instrument. This
will show how the mill people are deceived when they
imagine that they are approaching the limit of humidity
allowed by Act of Parliament, whereas, as a matter of
fact, they are scarcely within measurable distance.
Those who have had to make the calculations to
arrive at the percentage of humidity when worked out by
what are known as Glaisher's Tables, will know there is
a considerable amount of calculation, and if the observa-
tions are repeated and numerous, it is no small work to do
Now as the principle involved in the differential
value of the readings of the two thermometers follows an
exact mathematical rule, it must be obvious there can be
a mechanical method of reading the result without the
calculations by means of curves or diagramatic interpreta-
tion. This principle has been most ingeniously worked
out by an instrument-maker named Lowe in the town of
Bridgeport, Connecticut, U.S., A. With this instrument
it is only necessary to read the temperature of the dry
bulb (64°), then place the lower edge of the upper steel
finger, seen to the left of the instrument, opposite the
same temperature on the graded scale. This is done
by sliding the milled head up or down as required.
Then read the temperature of the wet bulb (58-7°),
and turn the same milled head until the upper edge
of the lower steel finger is level with that temperature.
In doing this you move levers which bring the point
of the indicator to that part of the chart where the
relative humidity (72%) can be read off— each of the
thick vertical curves representing 10%, and the inter-
mediate ones 2%. Other curves give the temperature
of dew-point, and the weight of vapour per cubic foot
of air. Upon testing, by exposing it alongside the
two standard hygrometers, I found it took the large
spherical bulbs of the thermometers four times as long
to adapt themselves to the temperature of the mill as
the long oval-shaped bulbs made by Casella of London;
and the scale, being graded on the brass mountings
instead of the stems of thermometers, gave reductions
showing 7% more humidity than existed. This differ-
ence may arise either from the thermometers having
slipped in the mount, or incorrectness of scale.
Another very ingenious instrument, "The Hygro-
phant," is one made by Huddleston of Boston, U.S., A.
This is even easier to understand than the preceding-
one, but confines itself to the finding of percentage of
humidity. Indeed it is so simple that it might be
called " Hygrometry made easy." First ascertain the
number of degrees of difference between the temperatures
of the wet and dry bulbs, then turn the vertical
revolving drum placed between the thermometers until
the figure in larger type at the head of the column on
the drum is the same as the difference of degrees;
then, reading on the central scale the degree of
temperature on the wet bulb thermometer opposite this
figure on the revolving drum, is found the degree of
humidity in the atmosphere. This instrument, as
received from the maker, was tested at a temperature
of 88", when four observations gave a mean excess of
humidity of 107o- The original heavy connecting
strands from the well to the bulb were then removed,
as they locally increased the humidity of the air near
the bulbs, and a connection composed of eight strands
of soft darning cotton was substituted, with the result
that the next four exposures showed only 4% of error.
These thermometers, too, were not graded on the
stems, nor had any of them been verified. I believe
these discrepancies would not occur if the instruments
were mounted with correctly made and verified
thermometers. Either pattern, on account of there
being no necessity for the use of tables and calculations
for reduction, would be very serviceable for mill use,
if constructed correctly as regards grading and after
having been tested.
I make this difference still more distinct by
appending a table of test experiments made by a
competent observer under the Kew Observatory rules
between the standard London instruments — having been
duly tested — and the thermometers of Huddleston's
instrument. The difference is remarkable and, as can
be seen, is greatest at the highest temperatures.
COMPARATIVE READINGS AND REDUCTIONS OF CASELLA'S
HYGROMETER AND HUDDLESTON'S HYGROPHANT.
Dry Bulb "
Wet Bulb °
Humidity "/o |
in the Shade.
In every case the instrument, to be reliable, must
comply with certain standard requisites : the distance
apart of the thermometers, the position of the well of
water, size of the aperture of the neck of the well bottle,
and the thickness of the strands conveying the moisture
from the well to the wet bulb. All should be in conson-
ance with the experience of those who have made a
careful study of this subject. In all cases of my
observation, two standard instruments were employed,
furnished with the same water, attached on opposite sides
of the same pillar or column of the mill ; and the
reductions were calculated from Professor Glaisher's
Hygrometrical Tables, 7th Edition, the tenths of a degree
in either bulb being worked out by interpolation with
the nearest factors.*
* Since the above was written Messrs. Casartelli of Manchester have produced a Mill HyHrometer
which conforms to the rcquircmcnta, theoretical and practical, lierein enunciated, and which is free from
tlic ordinary defects of this class of inbtrumeut. It has been tested against the standard Kew instrument
and found unimpeachable in accuracy.
HYGEOMETKICAL OBSERVATIONS IN COTTON SPINNING.
EEDUCED AS PER PROF. GLAISHER'S " HYGROMETRICAL TABLES," 7th EDITION.
No. 2 Sping.
„ 3 do.
„ 4 do.
,. 5 do.
No. 2 Sping.
„ 4 do.
„ 7 do.
No. 2 Sping.
„ 3 do.
„ 4 do.
„ 5 do.
No. 3 Spirg.
„ 4 do.
„ 5 do.
„ 6 do.
No. 1 Sping.
„ 2 do.
„ 3 do.
„ 4 do.
No. 1 Sping.
;, 2 do.
„ 3 do.
„ 4 do.
No. 1 Sping.
50 T— 78 W
„ 2 do.
„ 3 do.
„ 4 do.
HYGROMETRICAL OBSERVATIONS,— Co?)«Miuerf.
No. 1 Sping.
„ 2 do.
„ 3 do.
No. 1 Spiug.
„ 2 do.
„ 3 do.
No. 1 Sping.
„ 2 do.
No. 1 Sping.
„ i do.
,, 3 do.
„ 4 do.
No. 1 Sping.
60 T & W
„ 2 do.
70 T & W
,, 3 do.
62 T & W
No. 1 Sping.
„ 2 do.
„ 3 do.
„ 4 do.
No. 2 Sping.
,, 3 do.
„ 4 do.
„ 5 do.
HYGROMETER READINGS TAKEN IN JUNE 1894, TO COMPARE WITH
THE FOREGOING TABLES TAKEN IN WINTER, 1892-3.
No. 4 Sping.
„ 3 do.
No. 2 Sping
„ 3 do.
No. 2 Sping.
„ 3 do.
MILL IN RUSSIA PROVIDED WITH SPRAY HUMIDIFIERS.
The rooms of the mills in which the readings were
taken, the numhers spun in each mill, the percentage of
saturation of the outside atmosphere, the readings of the
dry and wet bulb, temperature of the dew point, elastic
force of aqueous vapour, weight of vapour per cubic foot
of air, weight of vapour if air was saturated, vapour
required for saturation of each foot of air, percentage of
humidity, (saturation point = 100), will all be found in the
It will be seen from the foregoing tables that there
is a considerable diversity in practice in mills spinning
much the same numbers and presumably much under
similar conditions. It will be further noticed there is
not the difference popularly supposed to exist between
the mills spinning extra fine and those spinning medium
numbers. As a matter of fact, there are no large modern
mills spinning very fine. This trade, such as it is, lies
pretty well in the hands of old established firms in
possession of ancient buildings which, although ancient,
are suitable for this class of work. It is, of course,
within tbe knowledge of all interested in the cotton trade,
that numbers, in the last twenty-five years, have become
gradually coarser, on the average, for better classes of
yarn ; the explanation of this being that improvements in
the exactness of process has enabled, in many cases,
single yarn to replace doubled yarn of twice the fineness ;
if not as perfect in result at least as perfect as the
competition in the article manufactured requires. Thus
the standard 60's twist of to-day replaces the 120's
doubled of 25 years ago.
I will now give an interesting comparison of a typical
mule room, the temperature at which the mills were
working, weight of aqueous vapour which the limit of the
Act of Parliament permits in weaving mills, weight of
water it would represent if condensed, the relative humi-
dity being given in each instance, compared with the
same quantities existing at the time the observations
were being made in four mills.
s s i
£ > a
£ ^ =*
O) 3 S
Q c3 a;
ID O JS
I give also a reproduction of photo-micrograph show-
ing yarn spun in mills "A," "B" and "C"; all being No.
60's twist. It will be seen that yarn " A " is a more solid
and regular thread than the others. I may say that
its test hi strength bears out this.
I have to call special attention to this illustration
because although the zincograph does not give quite the
whole of the detail of the photograph, it shows sufficiently
clearly the enormous difference existing. This difference
is quite as noticeable and striking in the whole of the
photographs that have been taken, that selected being
considered a fair average of the others.
The following table will show a microscopical test,
from which may be clearly deduced the superior regu-
larity of yarn in mill '*A", the different mills being
named by letters, "A," ''B," "C."
MICEO-MEASUREMENTS OF THE DIAMETER OF THREE
SAMPLES OF YARN.
MICROMETER LINES = g^ INCH.
'A"— 60's T.
No. of lines.
Mean — 8Jf
Range of 4 lines.
"B"— 60's T.
No. of lines.
Mean = 10||
Range of 5 lines.
C "—60's T.
No of lines.
Mean = 16
Range of 10 lines.
From the table of comparison of the fonr typical
mills on page 29 it will be seen that the mill "A"
approaches, in percentage of humidity, more nearly the
Act of Parliament than any of the otliers ; and this, in-
deed, is the only difiference that will explain the smooth-
ness and roundness and superior regularity. Of course,
the instances given are only typical, and carefully
selected as fairly average cases. I believe I can guar-
antee their exactness.
Having now endeavoured to show the importance of
this question of humidity, its relation to electricity, and the
want of similarity in practice, I will proceed to describe
the different methods adopted for the purpose of
regularising the moisture of the air, their success or
otherwise, and, finally, give an opinion as to the
temperature and humidity most desirable, and the simplest
and easiest method of accomplishing this.
UTILIZATION OF NATURAL EVAPORATION.
The simplest method of increasing the humidity of
the air in a room is by sprinkling water upon the floor
and trusting to the natural evaporation which, of course,
is more speedy with high temperatures than with low.
This is known, in Lancashire, as " degging," and is
practised to an extent hardly thought of, especially in
manufactories unprovided with more perfect systems —
more perfect only as referring to its automatic supply,
because evaporation from a regularly sprinkled floor
secures a diffusion of humidity, the regularity of which
cannot be surpassed. But the system is troublesome,
requires manual labour, is dependent upon the exactness
of an individual, and the continual dampness of the floor
is often supposed to cause rheumatic afflictions to the
workpeople. Again, in some weaving sheds, channels
have been made in the floor which have been partially
filled up with bricks, making a perfectly level surface,
with interstices. These channels drain down, generally,
to one end or side of the room and the water is allowed
to flow through the channels, the idea being that the
bricks will absorb the water and render it, by evaporation,
to the room. Further, these channels have, as a rule,
been taken under the looms. The writer much doubts,
however, if they are kept in actual operation in those
places where they have been constructed, the reason for
this being that the tacklers object to tackle the loom and
having to lie on their backs upon the damp bricks.
Further, the interstices between the bricks or tiles soon
get made up with the dirt and waste from the floor ; and
as the thorough cleaning periodically would be a consider-
able labour it is simply left undone. If the surfaces of
exposure were sufiicient, the required amount of humidity
could well be gained by this system, which would be satis-
factory — apart, of course, from its practical objections.
Another method of utihsing natural evaporation, and
one free from the objections named in the above remarks
is that of shallow water troughs making the circuit of the
room or crossing at different distances according to
requirements, the surface exposure of the troughs bearing
a relation to the cubical content of the room to be
humidified. These troughs are sometimes placed over
the heating steam pipes, at other times underneath, and,
occasionally, suspended from the ceiling joists without
reference to the position of heating pipes. In every
case the water is allowed to enter at one end of the room
and to flow, by gravitation, slowly along the troughs to
the other extremity, where the water is collected for
re-use, or for some other purpose. But this, after all, is
unimporfeant, the maiu object being to supply the water
at about the temperature of the room, and by sufficient
motion to allow the globules to be successively subjected
to the absorbing power of the air.
To deal with the advantages or disadvantages of these
three arrangements, I may say that where the troughs
are placed over the steam pipes they can be carried by the
pipes on brackets, and, as the steam pipes themselves are
generally regulated with a view of allowing the water
formed by condensation to gravitate to one extremity, the
troughs will also follow this inclination. The pipes being
underneath, the heat radiating has, of course, a tendency
to increase the natural evaporation. When the troughs
are suspended from the heating pipes the radiation also
acts upon the evaporation, and the troughs themselves form
a shield to prevent the direct rays of heat from affecting
the workpeople. * When the workperson has to stand directly
under the steam pipes, headache and nausea are often
produced. This would seem to be, then, in favour of this
system. Moreover, any leakage from the joints of the
steam pipe would fall into the trough instead of on to the
floor. Wliere the troughs are placed near the ceiling,
they have the advantage of not interfering with the
passage of hght to such a degree as when in other
positions, and, also, of being in that part of the room
where the heat is greatest and, consequently, the evapora-
tion most active.
There are partizans of each of these systems, but, as
they can all three produce practically the same result, I
will leave the matter as one of taste, only remarking, that
in considering this, the height of the room must be
taken into account.
* As between the positions of the trou;,'h above the stciiui pipe and unaerni ath, the relative evaporation
is:— above, 0-39in.; below, 46in., showing, an advantage in evaporation in favour of the troughs being
beiow, in addition to the further advantages enumerated.
The foregoing represents, briefly, all that has been
done in ntilising the principle of natural evaporation.
AETIFICIAL METHODS OF PRODUCING
We have now to consider the artificial methods of
producing moisture. In all systems the water, contained
in the air in a state of suspension, is either a chemical or
mechanical mixture. What I would say is that natural
evaporation means general diffusion and intimate and
atomic assimilation. Air and water so assimilated have
no tendency to separate until the conditions of temperature
or pressure have necessitated it.
Now in all mechanical appliances for distributing
fine particles of water in a proportionate quantity of
atmosphere, there is a limit to the power of atomization
or pulverization ; and, no matter what pressure be used,
the sub-division into particles is infinitely inferior in
number to the result of natural and free evaporation.
Therefore, any system of this kind, whatever its name
may be, can only be relatively advantageous as compared
with natural systems. If we take another illustration —
in a case where spray and vapour are produced by physical
force, such as vapour rising from the ground during an
excessively heavy rain storm, or the spray formed by a
gigantic waterfall — it will be found that the efl^ect of
the humid air is confined to a short radius round the
centre of action ; but wdiere the rising sun, heating damp
ground causes a mist this does not fall in the shape of
rain or dew, but is gradually absorbed owing to the
increasing elastic force of aqueous vapour. I hope this
will make plainer my remarks with regard to the difference
between chemical and mechanical moisture and afford
further proof of the advantage of the natural method.
Thus it is found by absolute observations that the
conditions of moisture in a room naturally humidified is
very much more equal than in any mechanical system.
This is explained by the facility with which natural
vapour can be assimilated by the neighbouring air, as
opposed to the mechanically powdered water ; and may be
illustrated by an example in chemistry where in a perfect
chemical solution it is possible to continue dilution until
the absorbed substance is one part to a million. In a
simply mechanical mixture the limit of dilution is quickly
reached. Thus all systems, which have, for principle, the
pulverization of water, have the initial defect I have
alluded to ; and they can at best be but a rough and
ready w^ay of attempting to solve what is, after all, a
EQUABLE HYGROMETBIC CONDITIONS.
In this regard I have some observations which show
how impossible it is to arrive at equable hygrometric
conditions with mechanical methods. The apparatus
employed w^as, perhaps, one of the best of the mechanical
systems ; the room was 150 feet by 50 feet, the height
about 13 feet, and the apparatus was placed about 15
inches from the ceiling. The action of the apparatus
was also assisted, as regards diffusion, by ventilating
tubes, which introduced fresh air at many points in the
No. 1 room showed the humidity of the air to be, at
10 inches from the apparatus, 95 per cent ; at 3 feet away,
the mean of a number of observations showed 75 per cent,
of humidity, at 12 feet away from one instrument it was
nearly CO per cent. In these cases, the temperature close
to the apparatus was 60 deg.; 3 feet off, 63 deg.; and 12
feet distant 71 deg. — showing, in addition to the differ-
ence in hinnidity, a considerable range of temperature
in the same room. There was, also, a well defined, but
inexplicable range of percentage of humidity 3 feet away
from the instrument, the range being no less than 12 per
cent from 11 o'clock to 1-40. This might be traced, no
doubt, to some accidental current of air. But more
extraordinary was the fact, absolutely proved, that in
10 minutes the temperature varied from 63-2 deg. to
65 deg., and the percentage from 77 to 68. At the
farther end of the room, 5 feet from a blank wall, with no
door or opening, the temperature changed, in 20 minutes,
from 68-4 deg. to 71 deg. and the percentage of humidity
from 621 to 56. In a similar room, but without
humidifiers, the observations showed a range of tempera-
ture of 4-2 deg. and 9 per cent, of humidity. The
variation would not have been so great as this but for
the fact that there were open windows at one end,
which decreased the percentage ; but the readings of the
observations were generally more equable. The tempera-
ture of the atmosphere outside was 47-3 deg. and the per-
centage of humidity 67.
As a further proof of the inefficiency of this system
of humidifying, I point to the fact that it is not practicable
to place this apparatus near moving bodies, such as
driving straps or shafts. In any case, where there is an
induced current of air, precipitation takes place. To
such an extent is this so, that the apparatus has had to be
moved from the centre of the room to the sides, to avoid
the action of the shaft and straps upon the air.
OBSERVATIONS WITH AND WITHOUT
I think it will prove useful to here append reproduc-
tions of photo-micrograph typical of woollen yarn spun,
with and without humidifiers on the day the observations
ORDINARY X 40.
It will be noticed that as iu the photographs of the
cotton yarns, the same result is apparent. That is to say,
the yarn spun under moisture is more solid, consistent,
and regular. The examples given were spun from the
same preparation, out of the same wool and the same
numbers ; although this is difficult to believe from the
photograph — multiplied 40 diameters.*
To make even still clearer to the eye the extra-
ordinary difference in the compactness of the fibre under
operation iu the various conditions of humidity or
dryness, I give another photographic illustration (see
page 40) of woollen sliver multiphed 20 diameters ;
No. 1 worked in the ordinary air of the mill, and
No. 2 in a room provided with humidifiers; the
numbers, fibre, speed of machines, and every condition,
except the humidity, being precisely alike.
In a visit to the United States, where, as I have said
previously, this question is one of great importance and
where many inventions have been tried, I had an
opportunity of inspecting various systems. I state
unhesitatingly, there was more or less precipitation in
every case of mechanical humidification. This will be
easily comprehended when I remark that, in a state of
the slightest motion, air will not carry a greater weight
than 80 per cent. And the quicker the motion of the air,
the greater the precipitation.
I scarcely know whether it would be time well
spent to discuss the bearings of the question of live
steam admitted in the working rooms. There may be
manufactories whore such a course is necessary, but I
do not know of any; and most certainly spinning and
weaving are not in the category. As has been pointed
* Whilst correcting the final proofs I liave been again struck witli the remarkable difference shown in
the photograph as between tlie two yarns. I can only attribute it to the fact that the magnified nhotoeranh
snows, and perhaps may ex^gfjerate, tlie pecuUar difference really exislinK- One thing I will guarantee is
that these yarns are fair samples of the bulk and that no attempt has been made to enlarge the differenrp
lor the sake of effect. »>i<.ciii,c
ORDINARY X 20.
out previously in this paper, live steam will increase
rather than diminish tlie electrical difficulty, particularly
with wool stock much more than with cotton. It is
exceedingly unpleasant to the persons working in the
room ; and, I think it is generally admitted, very
injurious to their health. It is therefore undesirable,
from every point of view; and as proper conditions of
the air can be so easily arranged in other ways there
would seem to be little excuse for a continuance of
this practice. I am glad to say that, personally, I do
not know of any mill in this country where such a
practice obtains, although I have seen it often enough
MECHANICAL versus NATURAL HUMIDIFIERS.
Taking into consideration the cost of the plant,
the power, the cost of supervision, the cost of replace-
ment and repairs necessitated where artificial humidifiers
are employed, and, above all, the inefficiency and
inequality of the result as compared with the system
of evaporation, I feel justified in declaring that, in
my opinion, the cheapest, most efficient, most regular,
and simplest method of maintaining a constant degree
of humidity in an enclosed body of air is the application
of some simple system of natural evaporation.
That it may be clearly understood what is to be
done to arrive at the best result for practical working
in cotton mills, I give a carefully prepared table showing
the readings of the dry bulb and the wet bulb, together
with the degree of humidity best calculated for the
thoroughly good working of the material operated upon.
It will be found that the results are much under those
allowed by the Cotton Cloth Factories Act of 1889.
Thus, take 90 degrees. The utmost humidity necessary
would be 49 per cent, as against 69 allowed by the Act ;
at 80 deg. it would be 52 as against 77*5 ; at 70 deg.
53 per cent, as compared with 88 ; and at 60 deg. it would
be 54 per cent, as against 88 per cent, allowed by the Act.
Thus leaving out the question of weaving sheds, which
require more humidity than spinning mills, cotton
spinners will see they have absolutely nothing to fear
if working under this Act of Parliament.
Humidity, and weight of vapour per cubic foot, for Spinning Kooms. at temper-
atures varying from 100'' to 40° F, and the temperature at which the
"Wet Bulb" Thermometer should read to attain it: —
4 3 grs.
In considering the (]uantity of water that should be
evaporated to produce the wished-for result in the
condition of the air it became necessary to experiment
as to the rate of evaporation at varying temperatures
and to endeavour to find a practicable working mean
that would simply require ordinary attention to maintain
the degree looked for. The mule rooms in mills of
to-day are built wider and higher than those in the
old factories. This necessitates an increased degree of
evaporative power. The condition of the exterior,
atmosphere requires to be still considered, and the
more this varies climatically, the more perfect should
be the apparatus to enable any requisite adjustment
to be made without unnecessary loss of time. Thus
in an east wind, any air admitted — which, of course,
is a constant occurrence, so long as work is going on —
reduces the temperature of the air in the room and
absorbs a proportion of the moisture, lowering the
general average. In winter, when the air admitted
might be fully saturated, introduced at, say, 30 deg., and
being saturated with some two grains of vapour per cubic
foot if raised to 80 deg. requires about 11 grains per cubic
foot to complete saturation ; thus calling for a moisture of
5| grains per cubic foot in the room to raise it to the
temperature and humidity requisite. This, and the fact
that the material itself is constantly absorbing some of
the existent moisture and that there is an inevitable
condensation constantly proceeding upon the windows
and upon the walls, requires that a quantity of vapour
should be replaced continuously. To effectually provide
for this is the problem I have had to solve.
It is nearly impossible to quote figiu'es of any
exactness to show the loss occasioned by the before-
named conditions — climate, position, elevation, exposure,
the nature of the building itself, the thickness and
fitting of the windows, the facility for the admission
of air through the doors, and the number of times that
the doors are opened, are all factors varying in different
mills, and it would be difficult indeed to lay down any
hard and fast rule.
Further, in considering the question in rehition to
the percentage of humidity desired, it must be borne in
mind that the temperature of the room is an important
factor in determining the amount of water surface necess-
ary to obtain the deficiency of vapour. Thus the higher
the temperature the more difficult it is to maintain the
percentage of humidity desired, and, therefore, the
greater the evaporative area requisite. For instance,
under similar conditions as between 81 degrees and 92-3
degrees the evaporation in the same time was, for the
lower temperature 0*14 inches and for the higher 0-295
each 24 hours.
This, of course, was simply an experiment in one
portion of the room under ordinary working conditions ;
but applied to the whole of the room the difference would
be more marked on account of the greater surface of
walls and windows conducing to condensation.
It may be interesting to show how the experiments
with regard to evaporation were conducted. In the first
place, they were all taken in an ordinary cotton mill
working under supposed normal conditions. A 5in.
evaporator was exposed in each position for 48 hours.
There were self- registering maximum and minimum
thermometers placed in close proximity and the readings
noticed each day the instrument was exposed. The
reason for the Sin. evaporator being used was to facilitate
the accurate measurement of the water evaporated by
means of the certified 5 in. rain gauge of the Meteorologi-
cal Society. The same iustruments were used throughout.
The proportion of evaporation between the 5 in. gauge
and one foot square as directly proportioned to their
surface was rather over seven to one.
In taking the capacity of the rooms in modern mills
and estimating the average temperature customary, it
may be fair to assume that the humidifying plant should
not have less capacity than that indicated by the evapora-
tive observations taken under normal working conditions
in order to maintain the standard amount of moisture
necessary for successful operating of the cotton. This,
carried a little further, and granting that a temperature
of 90 degrees Fahr. would be the extreme mean tempera-
ture at which the room might ever be heated — which,
it is hardly necessary to say would allow a considerable
margin for contingencies — it would require 3,552,120
grains of aqueous vapour to give a humidification of
50 per cent, in an ordinary mule spinning room of a
capacity of 360,000 cubic feet.
Now even in our humid climate in those mills
possessed of no artificial means of humidification it is
found that there are only some two million grains of
vapour present at a temperature of about 90 degrees.
The problem is, therefore, to introduce into the air
in this room about one and a half million grains more
vapour and to maintain that amount.
This means, shortly, that each 24 hours 205 lbs.
of water should be evaporated. Thus, taking the
ordinary mule room and the ordinary amount of
evaporation at 90 degrees as 2-163 inches per superficial
foot, it would require 758 feet of water surface to supply
In spinning rooms working at a mean temperature
of 90 degrees, a trough of water placed 9 feet from the
walls round the room, 15 inches wide at the top and
reduced by 2 in. steps as shown on page 47, would have an
area of water surface of 785 superficial feet. This I
believe would be the maximum required for humidifying
under the most adverse climatic conditions.
The illustration on page 46 shows a mule room
with the position of the steam pipes and evaporation
troughs. On page 47 various sections of troughs are
shown. The forms "A" and "B" are in practical use in
some mills; the one marked "C" has not heen tried
practically but is a suggestion of a method for securing
uniform evaporative surfaces throughout the area of the
room^ the theory being that if there is only one inch
of fall from the beginning to the end of the troughs
it will be possible to keep the level of tbe water in the
troughs between the limits of one of the steps, thus
maintaining a constant surface exposed throughout the
room and permitting of a measurable grading of the
amount of evaporation.
No other shape of trough except this stepped one
can be relied on to give equal results in all its leugth.
The trough is a suggestion of Mr. Midgley, Observator
to the Bolton Corporation, and is the outcome of con-
siderable thought and experience. Naturally there
must be a supply and exhaust tap for each system of
troughs. The method of supply and the dealing with
the waste water are subjects that are outside this paper
but will no doubt be intelligently dealt with in every
case. It is suggested there should be a 2in. supply
and a 2in. exhaust tap in order to allow speedy adjust-
ment of the evaporation and that the continuous supply
should be by means of a fin. bye-pass for the normal
current. A natural suggestion would be that the water
should be raised to the top of the building and allowed
to descend from room to room by gravity.
In the card-room, working at a mean temperature of
80 deg. or less, it would require 502,320 grains of vapour
more than exists ordinarily. This would be secured
by a superficial area of water surface of 560 feet. A
trough 9in. wide, (as shown on page 47, and marked
''D") diminished lin. each step, would fully supply the
A modern spinning mill equipped with the above
described apparatus and a certified hygrometer should
have no excuse for not being in the very best hygro-
metrical conditions for working the fibre to the very
best advantage. Seeing the extraordinary importance
of this portion of the industry it is to be hoped that
more attention will be paid to the matter than there
has been hitherto. The hygrometers should be read
two or three times a day and the temperature of the
dry and wet bulbs, together with the percentage of
humidity, entered in a register for the inspection of
the management. If this be done systematically and
carefully the average quality of the yarn produced in
this country will be improved; less cotton will be lost
in invisible waste and fly, and complaint of brittle,
hairy or "oozy" and uneven yarn should become a
thing of the past.
In the compilation of the whole of the foregoing
I have to most heartily acknowledge the very great
assistance I have received from Mr. Midgley. The
shortness of this paper and the condensed information
can hardly give an idea of the enormous amount of
labour that has been necessary to arrive at reliable
results. For myself I have had only one object, namely,
to throw as much light as I could upon what seemed
to me to be a terra incognita, and to assist, to the
best of my ability, the trade of cotton spinning in
which I am so deeply interested.
G. S. Heaton, Victoria Piunting Works, Bolton.
3 2922 00388 114 8
L;Pi:.C. COLL TS1577.D65 1894
^ Dobson, B. A.
^ Humidity in cotton spinning