Roberts, Dale & Company
John Dale was born in Birmingham on the 11th of May; 1815. He was educated in Birmingham and Warwick.  In the latter town was an
excellent schoolmaster, under whose care the subject of this sketch was placed, and to whose original and attractive mode of teaching
Dale attributed much of the acuteness and power of observation subsequently developed in him.

This teacher was accustomed to take his pupils out walking, and to ask them questions on all natural objects that they came across,
supplying them meanwhile judiciously from his own large fund of general information.

His school days at an end, John Dale went to Denbigh and was apprenticed to a chemist and druggist. Later on he removed to Rhyl,
where he had access to a number of chemical and pharmaceutical books, and no doubt in the prosecution of his studies, all his spare
moments were occupied.

He next proceeded to Manchester, and there acted as assistant to a Mr. Ansell, a chemist and druggist, a member of the Society of
Friends, who was also an acquaintance of the renowned John Dalton. This was in the period between the years 1833 and 1835.
(Ansell at that time was the only dealer in chemical apparatus to be found in Lancashire and Cheshire.) Under the circumstances it
was only to be expected that Dale would soon make the acquaintance of Dalton. That acquaintance once made, it soon ripened into
friendship, for John Dale became Dalton’s pupil. It was, moreover, but a foregone conclusion that so apt a pupil should be fired with
the enthusiasm and genius of such a master, and indeed Dale not long after this commenced a course of lecturing on chemistry in all
the principal towns of Lancashire. He received from Dalton especial commendation and, indeed, compliment on his skilfull and
original lecture-experimenting.

There now followed another slight change in a temporary removal to Altrincham. This, however, was soon succeeded by the return to
Manchester, where a shop was taken in St. Mary’s Gate, and it was during this period that Dale made the acquaintance of Mr. Thomas
Roberts, with whom, some years later on, he entered into partnership. In the interim he became manager of a calico print works in
Ardwick, and continued his duties in that capacity up to the year 1852, when he went to Cornbrook and started with Mr. Roberts the
chemical works, which under his directorship became famous, and made widespread the name of the Roberts, Dale, and Co. But
previous to the entry of John Dale, these works had been occupied in the manufacturing of dyewood extracts, British gum, and wood
spirit, and in the Exhibition of 1851, specimens of ultramarine manufactured by Kurtz were exhibited.  It is noteworthy that after the
formation of the new firm, numerous new methods of manufacture were introduced in place of older processes. This brings us to
about the year 1854, when the staple trade of the firm was wood extracts and British gum. About this period the paperhanging trade
began to develop, and the only colours then available were such as could be got at the oil and colourman’s shop, such  as Venetian
red, Verdigris, Bremen blue, &c. Dale now  introduced a much finer variety of colours; amongst them a much superior class of chrome
yellows, and he gave a great impetus to the trade by introducing his lakes made from wood extracts. Shortly after, the manufacture of
oxalic acid from sawdust by heating to fusion this material with the mixed alkalis, potash and soda, was commenced at the Warrington
works, which later on was managed by Dale’s eldest son, John. It was in accordance with a new process devised in Dale’s laboratory
and patented in 1856. The working of the new process, which marked a very important epoch in chemical industry, was undertaken in
conjunction with J. D. Pritchard, and subsequently brought to further perfection by Dale, and carried on until such time  as potash
became sufficiently cheap to justify its sole use.  Those who recollect the reports issued at that time of this process, will remember that
the mode of separating the alkaline salts was based on the fact that whilst the potash salt was soluble the soda salt was insoluble in
water. It is exceedingly probable that in connexion with the operations of this process, vacuum filtration on an industrial scale was
employed for the first time; such an accelerated method of filtration being, of course, highly desirable in connexion with the separation
of the oxalic acid solutions from gypsum, when the calcium oxalate obtained by causticising the insoluble oxalate of soda with boiling
milk of lime, came to be treated with sulphuric acid. No doubt John Dale was perfectly aware of Gay Lussac’s reaction discovered in
1829, by which carbohydrates and celluloses fused with potash yield oxalic acid. But he founded upon it the successful commercial
process referred to. Just about this period, too, the manufacture of solid caustic soda was commenced and successfully prosecuted.
The record now brings us to the year 1858, when Perkin discovered mauve, which he prepared from commercial aniline, using as his
oxidising agent potassium bichromate. In conjunction with Caro, who was engaged as chemist about the years 1860 to 1861, Dale -
now endeavoured to find an equally effective oxidising agent to bichrome for preparing mauve, and at length it was discovered that
copper sulphate, in conjunction with alkaline chlorides, answered the purpose; but to Dale’s discernment was due the further and
most important refinement of the process, involved in the judicious addition of a moderate amount of alkali. In fact, the obtainment of
the desired yield of colour depended upon this collateral neutralisation with alkali.   A distinct advantage was obtained in that, along
with a good yield of mauve, a black pigment was also produced, easily separated from the violet colouring matter and possessing a
special value of its own. The formation of this black colour is all the more interesting inasmuch as it may be said to have led to the
discovery of aniline-black by Lightfoot, to whom the reaction had become known.

In the meantime, C. A. Martius had been engaged as chemist at the Warrington works, and came there from Hofmann, in whose
laboratory he had acquired a sound theoretical knowledge of the then recently discovered aromatic bases such as phenylene diamine,
dimethylaniline, &c. He was at once set to work by Dale with the object of preparing new colours from such aromatic bases, through
the medium of nitrous acid obtained from nitrite of soda.

From this course of experiments directly sprang the manufacture of Manchester brown (“Bismarck brown“), and Manchester yellow
(“Martius yellow“).

The patent for the Manchester yellow was taken out in the joint names of Dale, Caro and Martius (Eng. Pat. 2785 of 1864). Ordinary
Aniline yellow or amido-azobenzene (“Fast yellow”) was next placed in the market. The induline group, so named in the patent taken
out by Dale and Caro (Eng. Pat. 8307 of 1863) was discovered about this period. Somewhat before this date, John Dale had
commenced the manufacture of picric acid, first from Australian gum, and later on more advantageously from commercial carbolic acid.

Then followed the manufacture of aurin, which was also commenced about this period.  John Dale’s youngest son, R. S. Dale, was
now set to work by his father upon the aurin process, which he completed, and in conjunction with Schorlemmer, wrought out the
theoretical development of the subject, and with Schorlemmer succeeded in converting aurin into pararosaniline, thus establishing it
as a triphenylmethane derivative (this Journal, 1885, 476). Further aniline colours were later on prepared in Dale’s laboratory, and
afterwards manufactured in the works. Among the names of those noted chemists who were engaged in Dale’s laboratory were those
of Caro, Martius, Schad, Leonardt, and Koepp.

There were some novel and original processes devised and carried out during this period of great activity, which it may be interesting
to notice. First and foremost amongst these was the use of the caustic soda and potash boiler, in which the evaporated water was
utilised as steam, and consequently the fuel used in the evaporation was rendered more efficient, the steam being used for driving
engines, whilst by the aid of this steam under pressure, the concentrated caustic liquors were at length, or when desired, forced over
into a caustic pot, and there finished in the usual way. This method of working was modified later on, to the still greater economy of
fuel, by the addition of vacuum apparatus, at the suggestion of Dale’s youngest son.

A similar process and apparatus were subsequently used for the boiling down and recovery of esparto liquors by
R. S. Dale.                             

But not only was the mind of Dale fertile and resourceful as regards manufacturing methods, but his ardent study of the pure science
now stood him in good stead as regards analytical and valuation methods, and it is a fact that he mainly devised his own analytical
processes. For example, the method for estimating tin with potassium bichromate was his, as was also that for determining indigo by
reduction with copperas and lime, a vessel of water being connected with the closed vessel containing the reducing solution. As soon
as the reduction was perfect (a siphon tube with tap connecting water vessel and reduced indigo solution) the tap was opened, and the
volume of water sucked in corresponding to that of the oxygen absorbed, gave the data for calculating the weight of indigo present in
the sample. It is believed that this method is now published for the first time.  Another remarkably ingenious process was that devised
by Dale as a rapid means of estimating in a quantity of the mixed alkalis, potash and soda, the amount of either. Each estimation only
occupied half an hour. It was a volumetric method and was accurate to half a per cent.  Standard solutions of potash and soda were
prepared.  The mixture of the alkalis was taken and to it was first added a solution of tartaric acid to the point of neutralisation, and then
just as much again for the production of bitartrate.   The bitartrate of potassium being insoluble in a solution of bitartrate of soda of
about 6° Tw., was fully precipitated. Filtration from the crystalline potassium salt now rapidly followed, and the precipitate was lightly
washed with water, and both filtrate and precipitate were then separately treated with the respective solutions of known strength of
potash and soda, whereby was alkalimetrically determined the excess acidity due to the bitartrates, and hence the amounts of the
alkalis themselves present. R. S. Dale then modified his father’s process, so as to render it available for mixtures of the chlorides and
sulphates of the mixed alkalis respectively. These may serve as a few examples of many ingenious and highly useful commercial
assay methods devised by Dale.  During the last four or five years Mr. Dale’s health had been failing, but his interest in the later
developments of all branches of chemical industry had never flagged in spite of this.  His loss will be greatly felt in the business, with
the interests of which he has been so long intimately connected. Very few chemists connected with the papermaking, calico printing
and textile industries failed to apply at one time or another to him for counsel and advice, and never failed to obtain the assistance they
desired. He died May 31st, 1889, and thus another of those great lights of former days, which have contributed to render lustrous the
name of the Literary and Philosophical Society of Manchester, is removed, and we may truly say that whilst Joule stands preeminent in
physical research, and Dalton in chemical theory, that John Dale, Dalton’s pupil, takes rank as a typical representative of the
successful application of chemical science to chemical industry.—W. S.
Reproduction of Obituary of John Dale, F.C.S. and co-founder of Roberts, Dale & Co.,
Journal of the Society of Chemical Industry, July 31, 1889, pp. 528-530:
Report on Manufacturing Chemistry in South Lancashire-1861
History of British Dyestuffs Corporation and ICI
Picric acid explosion on June 22, 1887 wrecked
the Roberts, Dale & Co. plant in Cornbrook and
killed a worker.  The plant soon closed.

Photo:  Courtesy of TUC Library Collections,
London Metropolitan University.  Click to enlarge.
Reproduction of "Report on the Circumstances Attending a Fire and Explosion at Messrs. Roberts, Dale & Co.'s Chemical Works,
Cornbrook, Manchester.  Gov. Report No. 1xxxi, Colonel V.D. Majendie, C.B.",
Journal of the Society of Chemical Industry,
December 31, 1887, p. 835:

This exhaustive report shows that the articles manufactured on the side of the works where the explosion occurred were picric acid,
nitrate of lead, nitric acid, hydrochloric acid (nitre cake .and salt cake), tin crystals, tin solutions, nitrate of iron, nitrate of copper, aurin,
Manchester brown, Manchester yellow, lakes for paper stainers and emerald green. Such raw materials as carbolic acid, sulphuric
acid and litharge, the litharge being used for making nitrate of lead, were all present, the latter salt in very considerable quantity; some
nitrate of strontium was also present.

A fire commenced the catastrophe, this breaking out at or near the stove used for drying the picric acid. The fire spread quickly, and in
five or six minutes an explosion followed, but not one of an alarming character.  This explosion came from the site of the picric acid
stove as nearly as it can be located. It was followed in something under a minute by a second explosion of an appalling character, and
attended with disastrous results in the shape of damage. One life was lost.

There is little doubt that the fire was caused by the carelessness of a workman, who was smoking. Several theories are advanced to
explain the first and lesser explosion, but the second, which was so disastrous, was in all probability due to the blazing and molten
picric acid coming in contact with the litharge placed in close proximity and with the nitrate of lead and nitrate of strontium. It would at
once combine with these and form fearful explosives.  Picric acid alone can scarcely be called an explosive, but if it comes in contact
even with plaster or lime, it forms a picrate of highly explosive character, and it is shown that picric acid mixed with a litlle litharge inthe
cold, produces a mixture which explodes much more readily than picric acid alone.

Finally, the precaution is urged, that in the manufacture of picric acid the separation of the acid fromall other substances or ingredients,
contact with which would be likely to produce under favourable conditions a
picrate or explosive mixture should be carefully seen to.

“At present picric acid and picrates appear to fall within the category of ‘explosives,’ and to be subject to the Explosives Act, 1875, only
when they are ‘used or manufactured with a view to produce a practical effect by explosion or pyrotechnic effect.’“             .

“In view of the present disaster,” Colonel Majendie proceeds, “and of the results of my experiments it will be a matter for careful
consideration whether it is not necessary in the.interests of public safety to take advantage of the powers conferred by the 104th
section of the Explosives Act, 1875, and to extend the definition of explosive to picric acid and all picrates, for whatever purposes
manufactured, and to apply the same provisions of  the Act, subject to such exceptions, limitations and restrictions as may appear
reasonable.   This point, however, is one which, in the interests of the trade, as of the public, demands the fullest and most careful

As to the storage together and in close proximity of the several substances which resulted in the formation of such fearful explosives,
Colonel Majendie stigmatises it as the result of negligence.—W. S.
Map of Cornbrook Location of Roberts, Dale & Co.
Explosion at Roberts, Dale & Co. Works on June 22, 1887
Photos:   Courtesy of
Manchester Archives and Local Studies.   Click to Enlarge.
Damage to Home of Foreman Mr. Reilly
Damage to Office of Foreman Mr. Reilly
Destruction of Mr. Thornton's Boatyard Near Roberts, Dale Works
1882 Map of Roberts, Dale & Co. Mersey Bank Chemical Works in Warrington
ColorantsHistory.Org thanks Mr. Thomas Jackson for supplying historical information about Roberts, Dale & Co.
Mr. Matthew Jarvis, a descendant of Mr. James Martin, who was killed by the explosion in 1887, is commended
for contributing the news article "The Inquest".
Reproduction of news article "Fatal Explosion at Manchester", The Times, June 23, 1887:

An alarming and destructive explosion took place at noon yesterday at the Cornbrook chemical works, Manchester, belonging to
Messrs. Roberts, Dale, and Co.  Up to a late hour yesterday the exact cause of the disaster had not been placed beyond doubt, but it
appeared that a fire had broken out a few minutes before in one of the rooms, and it is supposed that sparks fell among some
explosive mixtures.  A fireman in the service of the firm, named James Martin, was found dead with a brass jet in his hand, as though
he had been hastening to his work when an explosion followed.  He was killed by a wall being blown upon him.  There were two
explosions in succession, one a few seconds after the other, the second being the more violent, but both were of such force as to
shake down walls and do other serious damage in all parts of the works, while the effect for a considerable distance round was to
break windows, furniture, and fittings of houses and cause persons to rush into the streets.  A dense volume of smoke was seen
issuing from the works, and the city Fire Brigade were soon there in great force.  The buildings were partly of brick, and were found
already in ruins from the shock, but flames were issuing from several places, and the smoke being charged with chemical gases the
firemen had not a little danger and difficulty to contend with.  The apprehension of further explosions did not deter them, and they
worked with admirable steadiness for some hours till the fire was overcome, not only in the chemical works, but also in the
neighboring premises of Pomona Gardens, which had been ignited in a dozen places by the lodgment of burning material.  Both the
Agricultural Hall and the Pomona Palace, the scenes of many local festivities and of political gatherings of importance, were seriously
damaged by the fire.  The wreck of the chemical works blocked the roadway, and the firemen had great difficulty in getting near those
buildings with the engines.  Some of the workpeople, of whom there were about 50 at the works at the time, had to jump from story to
story as the staircases were destroyed.  It is possible that some passers by may have been overwhelmed by the falling walls or struck
by the stones, bricks, iron piping, and other fragments which were shot to great distances by the explosion.  Some of those fragments
fell on the roofs of buildings on the other side of the Irwell.  Great damage has been done in Ordsall Lane to the mills of Messrs.
Haworth, the dyeworks of Messrs. Worrall, and the chemical works of Messrs. Hervey.  About a score of workmen and girls were
treated at the Salford Hospital for cuts and contusions received either while in mills or walking near them.  Fortunately the scene of the
explosion was in a comparatively open space, but the concussion was severely felt over a large area, the outer walls being blown
across the road for more than 20 yards.  A house near the works is an utter wreck in it interior, the contents being broken and flung
together in all the rooms.  Thousands of persons flocked to the spot and detachments of the 13th Hussars and the 1st Lancashire
Fusiliers were engaged in keeping back those who pressed too near either for their own safety or the work of the firemen and police.

Late last night it was found that another death had been caused by the explosion.  A child named Heled was lying in a cradle in a
cottage near the works, and the force of the explosion dashed it with fatal violence against a wall.

Reproduction of 1887 Manchester Police newspaper article "The Inquest":

The Manchester deputy coroner on Friday opened an Inquiry into the cause of the death of James Martin, fifty-four, who was killed by the
explosion at Messrs. Roberts, Dale and Company’s chemical works, Cornbrook, two days previously.  Mr. J.M. Bates, barrister, who
represented Roberts, Dale & Co., expressed their deep regret at the explosion, which had deprived them of one of their most valued
servants.  His clients were present to render to the court and to Colonel Majendie, the Government Inspector, every assistance in their
power.  The cause of the explosion was wholly unintelligible to them, the more so as they had manufactured picric acid in this shed for
the last thirty years without danger or injury to anybody.  The jury then went to view the scene of the explosion and the dead body, and
on their return evidence was called as to the cause of the fire, which, it is supposed, originated the explosion.  Peter Heald, a mechanic
in the service of Messrs. Roberts and Co., said he was working there on Wednesday morning when he heard that a fire had broken out
a minute or two before twelve o’clock.  He attached a hose to the water plug, while the deceased man Martin went and held the jet in
the road, just under the window where the picric stove was.  The fire appeared to be near the centre of the sheds in the yard.  Witness
turned to go away as he heard the explosion, and thought the deceased was following him.  When he got about twenty yards away he
turned round and the whole of the works appeared to have blown up.  In the shed where the fire took place picric acid, nitrate of lead,
tin, crystals, and, he believed, aqua fortis, were kept.  Joseph Dean, storekeeper at the works, said he did not see the fire when it first
broke out.  He saw the fire before the first explosion.  Witness went inside the shed, and stood about four yards from the fire and close
to the picric stove.  The fire seemed to be floating about; he had seen similar fires before, but not so large as on the present occasion.  
One of the previous fires was attributed to the men smoking, and that was strictly prohibited.  When he first went across to that part
where the accident happened a man named Hyde had his pipe lighted.  Witness spoke to him, and Hyde who was ready to go home,
pulled his pipe out of his mouth and directly afterwards left the works. To light his pipe he would have to use a match, and witness
heard a stove door close just before Hyde emerged from the building smoking his pipe.  Hyde was not drunk, but apparently had a
glass or two.  The men sometimes went to the Pomona Gardens for a drink, but they were fined if they brought drink on the premises.  
Stephan Logan, who said he was a labourer, said he never saw Hyde smoking, nor did he think Hyde had had any drink.  Robert Hyde,
a labourer, said he was working with Logan on Wednesday, taking picric acid out of the stove and placing it in barrels.  He noticed
nothing unusual about the place and he was quite sober.  After the stove was emptied, witness turned the steam half-off.  He was not
smoking then, nor did he light his pipe before he left the works.  He had smoked many a time in the works, and once he was caught
and fined.  The inquiry was then adjourned to July 14th, by which time Colonel Majendie will have prepared his report.
History of Yorkshire Dyeware & Chemical Co.