IMPROVEMENTS IN THE MANUFACTURE OF INDIGO
Year: 1850

page_text: AIME MARNAS, of Lyons, France, send greeting..
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent, under the Great Seal of the United Kingdom of
Great Britain and Ireland, bearing date at Westminster, the Twelfth day of
December, (One thousand eight hundred and fifty) in the fourteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Jean Aime Marnas, my exors, admors, and assigns, Her especial
license, full power, sole privilege, and authority that I, the said Jean Aime
Marnas, my exors, admors, and assigns, or such others as I, the said Jean
Aime Marnas, my exors, adiñiors, or assigns, should at any time agree with,
and no others, from time to time and at all times during the term of years
therein expressed, should and lawfully might make, use, exercise, and vend,
within England, Wales, and the Town of Berwick-upon-Tweed, my Invention
of "IMPROVEMENTS IN THE MANUFACTURE OF INDIGO;" in which said Letters
Patent is contained a proviso, that I, the said Jean Aime Marnas shall cause
a particular description of the nature of my said Invention, and in what
manner the same is to be performed, by an instrument in writing under my
hand and seal, to be inrolled in Her said Majesty's High Court of Chancery

page_text: within six calendar months next and immediately after the date of the said
in part recited Letters Patent, as in and by the same, reference being
thereunto had, will more fully and at large appear..
NOW KNOW YE, that in compliance with the said proviso, I, the said
Jean Aime Marnas, do hereby declare that the nature of my said Invention,
and the manner in which the same is to be performed, are fully described
and ascertained in and by the following statement thereof, that is to say:―
My Invention consists of the use of a cheap material (in the preparation of
soluble indigo blues) instead of the expensive one now used, and which yields a
superior product both in quality and quantity. The soluble indigo blue, called
Saxony blue, has hitherto been prepared in the following manner. The sul-
phate of indigo being thrown in water, woollen skeins, or better still, woollen
stuffs, are dipped in, which imbibe the blue, and leave in the water the sulphuric
acid and the foreign matters; these stuffs are washed in cold water, then they
are dipped in hot water slightly alkalized, the water retains the blue in solution,
and the wool being thus freed from the color can be used anew. The blue
liquor is slightly acidulated while yet warm, and deposits a green matter,
soluble in an alkaline liquor, but which settles in an acid liquor; the water is
poured off; the blue may then be used as it is, or purified a second time by the
same means if a purer blue is required.
According to my Invention, instead of the skeins or woollen stuffs, 1 make use
of waste wool, and particularly of flock wool, or shearings of cloth and other
woollen stuffs. This matter offers several advantages,―
Firstly, in its almost pulverous state it presents a great deal of surface, and
consequently it takes up a much larger quantity of colouring substance.
Secondly, its cost is very trifling and in a manufactory which would require
two thousand pounds worth of woollen cloth the expense in flock wool might
not be above twenty pounds.
Thirdly, and this its chief advantage,-it yields very easily and without its
being injured, the blue it has taken up. Woollen stuffs, by the effect of their
texture, of the twisting, and the capillarity of the yarn, and also by the effect of
the felting, which increases at each operation, retain a large amount of blue,
which cannot be extracted but with difficulty and always with injury. The
woollen stuffs themselves very soon loose their absorbing properties, the parts
most exposed to the action of warm alkaline water are converted into a some-
what gummy matter, which deoxidizes and destroys in each operation a certain
quantity of blue. Flock wool, on the contrary, presents all its internal and external
surfaces to the action of water, it renders the colour as easily as a sponge, the water
may be used at a lower degree of heat, and be less alkalized; flock wool dete-

page_text: riorates less, does not become gummy, and may be use for a much longer
time. :
:
Lastly, in estimating at ten per cent. the saving merely on the spoiled blue,
it will be underrated, and, nevertheless, it is considerable in a manufactory of
some importance. The process with flock wool is the same as with stuffs.
The sulphate of indigo is thrown in and the acid liquor is slightly heated, the
flock wool, previously.cleaned, is put in, then in half an hour or thereabouts, the
liquor is drawn off, in which a new quantity of flock wool is put in, and so on
until the whole of the colour be absorbed. Flock wool which is not completely
saturated, is put again in in the liquor in which some colour still remains, and so
on in succession. Cold water is thrown on the flock wool, after it is drained; it
carries off the acid and the soluble green. The flock wool is then thrown into
a small quantity of warm water slightly alcolized by potash or soda; it is well
stirred and put in bags by means of wooden shovels, then pressed; the liquor
which runs off is to be slightly acidulated and filtered whilst yet warm; the
green matter insoluble in an acid bath remains upon the filter, and the soluble
blue passes through it purified and sufficiently concentrated to solidify in
cooling. The operation may be repeated in order to obtain a purer blue. In
evaporating at a low temperature indigo carmine may be obtained more or less
concentrated suitable for dyeing and printing on cloth, and for the preparation,
by proper thickening, of the various soluble blues for linen painting, &c.
Flock wool becomes useless by prolonged usage, retains yet all its value as a
substance which contains nitrogen either for manuring or the manufacturing
of prussiate of potash. The acid waters may be concentrated and used in the
manufacture of various sulphates, copperas for example, or be mixed with col-
cothar, in order to produce by calcination the fuming sulphuric acid called
"nordhausen" acid, which is very suitable for dissolving indigo. The same
colcotha may be used indefinitely, (the details of the manufacturing of this acid
by this method are to be found in several works on chemistry, particularly that
of the Berzelius. As I have no intention of indicating improvements in such
and such preparation of blue, of sulphuric acid, of sulphates, &c., I do not enter
into the particulars of these various manufactures, and I wish it to be well under-
stood that I do not claim any right of Invention for these; I merely indicate
that the blue extracted by my process can be applied to all the products which
have for their base the sulphate of indigo, and also a means of making the
refuse of the operation available. I limit myself to claiming the Invention of a
better and more economical process or method of preparing the Saxony blue,
and of extracting easily, economically, and entirely, the indigo blue from the
dissolving and washing waters produced in the manufacture of indigo, carmine,

page_text: and other soluble blues; and I sum up this process in saying that it principally
consists in the employment for this purpose of waste wool, and particularly
flock wool, which combines in itself all the necessary properties:
In witness whereof, I; the said Jean Aime Marnas, have hereunto set
my hand and seal, this Twenty-sixth day of May, One thousand eight
hundred and fifty-one.
!:
....
JEAN AIME (L.) MARNAS.
AND BE IT REMEMBERED, that on the Twenty-sixth day of May, in
the year of our Lord 1851, the aforesaid Jean Aime Marnas, came before
our said Lady the Queen in Her Chancery, and acknowledged the Speci-
fication aforesaid, and all and every thing therein contained and specified;
in form above written. And also the Specification aforesaid was stamped
according to the tenor of the Statute made for that purpose.
Enrolled the Twelfth day of June, in the year of our Lord One thousand
eight hundred and fifty-one.