September SO, 1871.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
275 
abrasion, a harbour for the dust and dirt, and is thus 
rendered far from, ornamental to the place of its attach¬ 
ment. 
The temperature at which the mixture of gum and oil 
Intended to be used melts is now recognized as forming 
a basis for the temperature to which the oil is to be 
heated previous to the introduction of the melted gum, 
the whole running, when the two are fairly incorporated, 
being also kept much under the degree of heat which 
was formerly considered necessary. In fact, it is in this 
respect that the present mode of varnish-making chiefly 
differs from the modes formerly employed, the greatest 
care being now taken to keep the temperature throughout 
the process as low as is consistent with perfect admixture 
of the several ingredients. 
The next point to which I shall direct your attention 
is the apparatus used for the modern process of varnish- 
making. In the first place, iron vessels generally take 
the place of copper ones for all common varnishes, the 
bottom of the gum pots alone remaining copper, as here¬ 
tofore. The lower temperature employed is found not 
to affect the metal, and the introduction of impurities 
from that source is no longer feared. 
In the next place, instead of heavy copper stirrers, 
light thin plates at the end of the rods are used to cut 
the gum, etc., the greater velocity with which they can 
be manipulated securing moi’e perfect mixing than of 
old. 
In the third place, a tramway is laid down from the 
furnace in which the mixed gum and oil is heated, which 
^usually runs from the shed into the open air. If, there¬ 
fore, from any accident the mixture takes fire, it can be 
at once removed to a place of safety, where it can be put 
>out at more leisure. 
The boiling-pot, which holds about 100 gallons, has a 
■closely-fitting conical cover, which, if it can be put on, 
.at once extinguishes the flame if it be not too far ahead. 
The last improvement has only recently been introduced, 
and is not yet generally adopted. Two galvanized iron 
^shafts are erected side bj 7- side; one corresponds with the 
gum pot, the other with the boiling-pot; the upper end 
of these shafts alike communicates with the main furnace 
•shaft. The lower ends are fitted with caps, which arc so 
balanced by counterpoises that they can be slid up or 
-down their respective columns. To these caps heads are 
attached at right angles, which can be brought over, and 
which fit closely on to the gum pot and boiling-pot re¬ 
spectively, and, when in that position, have free com¬ 
munication with the chimney-shaft. The front of each 
hood is cut away and fitted with a diaphragm, slit in such 
a manner that the contents of the pots can be stirred, 
and is removable when it is desired to see into them. 
The advantages of this arrangement are obvious with¬ 
out further description; in place of the workmen being 
annoyed by the dense and pungent vapours which 
escape from the heated gum and oil, the whole are re¬ 
moved, and nothing whatever comes into the air of 
the shed except at the time when a pot of the gum is 
being tilted into the boiling-pot, or when the whole has 
to be removed into the air. The reduction of smell, as 
regards the neighbourhood, is so great, that in the com¬ 
paratively rare intervals when a disagreeable vapour 
does come off, the air of the yard mixes with it suffi¬ 
ciently to neutralize the effect exterior to the works. 
This last improvement is due to Mr. Bewicke, of Hack¬ 
ney AVick, who, in consequence of a disastrous fire at 
Ms works having been caused in a great measure by 
the men being so suffocated with the fumes from the 
boiling-pot that they were unable, when it took fire, to 
extinguish it in time, has been impelled to seek for such 
more perfect appliances as would bring the whole system 
more under control than had previously been the case. 
I think you will agree that the plan deserves to succeed, 
and from the experience it has already had, I believe it 
will do so. Old varnish makers-, standing at the fur¬ 
naces when they are in full operation, seem at first 
almost at a loss to know what stage of the process they 
are at, from the want of their accustomed choking 
miasma. 
Discussion. 
The Chairman, in inviting discussion on the subject, 
said, if any members of the trade were present, who 
could furnish the meeting with any of the information 
which it would seem was rather kept secret, it would, no 
doubt, be of great advantage. 
Mr. Tinne said he had hoped some practical man 
w'ould have made some remarks on the subject, which 
he thought would be of great value. It was one very 
interesting to him, as he had seen abroad, especially in 
Holland, the beautiful character of what was there called 
porcelain painting, and he believed its great merit arose 
from some particular purity in the preparation of their 
boiled-oil and varnishes. He had been specially anxious, 
in the painting of his own house, to apply that same 
beautiful white porcelain painting which ho had seen 
in Holland, but as yet he had not seen anything of the 
kind in this country. Allusion had been made to this 
improved process having originated in Germany, and no 
doubt Air. Vincent was aware that the same thing 
existed in Germany as he had alluded to in Holland, 
and which might be noticed even on the Dutch ships 
which came to this country. He should much like to 
see the same kind of thing introduced here, for, unfor¬ 
tunately, what was called porcelain painting generally 
turned very yellow in a short time. He could only 
ascribe this to either ignorance on the part of the work¬ 
men, or impurity of the materials employed; and ho 
hoped, therefore, that some improvement would soon be 
made. 
Air. Nicholson said, with reference to what had just 
been remarked about oil not being produced in this 
country capable of keeping the colour of the paints used 
in its original brightness, it was well known in the trade 
that there was an oil almost colourless, which was used 
largely by decorators for the finer class of work. It 
was an oil which had not been heated in any way, but 
simply oxygenated, and it had a powerful drying ten¬ 
dency, ^almost equal to that of boiled-oil; and if Air. 
Tinne would confer with any decorator of note, ho -would 
tell him that that oil was in constant use. He had been 
much struck with the low temperature referred to by 
the lecturer in the boiling of oil, which he thought was 
about 260 degrees, and that the oil then showed no fatty 
tendency. It was, however, well known in the trade 
that oil might be boiled up to 600 degrees without show¬ 
ing any such tendency; in fact, that was the ordinary 
heat to which it was subjected in the process of trial 
before used for varnish-making. An oil would hardly 
show its impurities at a less temperature, certainly not 
under 500 degrees; at all events that was the opinion of 
the trade. With regard to varnish-niaking, the method 
described seemed to him somewhat of a primitive nature, 
for there was a process in common use whereby the 
whole of the vapour arising from the oil-pot and from 
the gum-pot was wholly absorbed and condensed into 
liquid, not passing into the chimney at all. 
Air. Vincent said he had great pleasure in agreeing 
with what had been said by Air. Tinne with regard to the 
character of Dutch and German paintings ; and it was 
really the fact that the oils which were boiled abroad 
had that characteristic which had been spoken of. They 
were, as a rule, paler than oils boiled in England, and, 
having no driers dissolved in them, they did not dete¬ 
riorate the colours with which they were mixed, and 
thus the maximum of brightness was attained. He 
supposed the last speaker had referred, to what wa3 
generally called “ French oil varnish,” which was a thing 
which had been known in the trade for the last thirty or 
forty years for the purpose of mixing with pale colours, 
and for producing very lightly coloured delicate pamts. 
What he aimed at was this. There were a large number 
of persons in the trade who were not aware of the great 
