| 
| as is contained in the glazes used for similar purposes in this 
| country. 
(Compare table 1 on page 38 of the report, giving the 
percentages of lead monoxide found in certain earthenware 
glazes used in Staffordshire, with the percentages of lead oxide 
found in the foreign glazes, mentioned on pp. 16-25 of the 
report. ) 
(6) The lead compound used in these foreign glazes is either 
a bisilicate of lead (PbO2SiO,), or a compound silicate contain- 
ing as bases oxide of lead, alumina, lime, and alkalies (report, 
pp- 16-25). 
(7) Wherever these compounds have been introduced in 
place of white lead, lead-poisoning has disappeared (report, see 
pp. 17, 18, 20, 25). 
(8) The foreign manufacturers above mentioned use ‘‘ lead- 
less * glazes no more than English potters do. 
(9) Women and young persons are employed at these factories 
as dippers, dippers’ assistants, ware cleaners after dippers or 
glost placers, and yet there are no cases of lead-poisoning. 
The statements thus briefly presented are an accurate sum- 
mary of the information contained, on these points, in the 
report, and it is evident that they furnish no warrant for the 
first and fourth conclusions arrived at by Profs. Thorpe and 
Oliver. No one doubts that it would make assurance doubly 
sure to prohibit the use of lead in the glazes used on 
seven-tenths of the pottery produced in the ‘‘ potteries” 
district of Staffordshire. The report contains very little 
evidence to show that such a cutting of the Gordonian 
knot is practicable, while it furnishes ample evidence that so 
drastic a regulation is not required to abolish ‘* plumbism.” 
English potters, from the time of Josiah Wedgwood down to 
the present, have made numberless experiments to produce 
leadless glazes. In a paper by Mr. W. P. Rix, published in 
the Fournal of the Society of Arts of March 3, 1899, an ac- 
count is given of the best known of these, and it is shown 
clearly that in almost every case their use has been abandoned, 
in some cases after a very lengthy trial, because of practical 
difficulties connected with their production, which made them 
too uncertain for general use. The experiments to which 
Profs. Thorpe and Oliver refer on p. 9 of their report are too 
recent and too incomplete to afford any justification for the 
sweeping statement made on that page in the following words, 
the italics being mine :— 
‘We have no doubt whatever that leadless glazes, of sufh- 
cient brilliancy, covering power, and durability, and adapted to 
all kinds of table, domestic, and sanitary ware, are now within 
the reach of the manufacturer.” 
As a matter of fact, it 1s known to every practical potter 
who has experimented with leadless glazes, and to none better 
than those who are working with them at the present time, 
that leadless glazes of sufficient stability—z.e. containing a 
sufficiently high percentage of alumina to bring them into 
agreement with the ware—do not become fluid (or ‘‘ flow,” as 
the potter calls it) in the firing to the same extent that lead 
glazes do. They are, consequently, deficient in that ‘* covering 
power,’ as a potter understands the term, that Profs. Thorpe 
and Oliver claim for them. 
At the general firing temperature of English earthenware 
glazes, a leadless glaze, even of the very latest type, becomes 
clear and glossy, but it does not become fluid. It follows 
from this, that the slightest inequality of thickness produced 
in the dipping remains after firing; that any small bit 
knocked or chipped out of the glaze coating before it is 
fired—an accident of the most ordinary occurrence—leaves a 
bare spot, for the glaze cannot flow over the space as a lead 
glaze would; moreover, the mending of imperfectly glazed 
pieces before firing is rendered almost impossible for the same 
reason. These points are of the utmost importance in practice, 
for, while greater care must be taken in sorting the bisque ware 
before dipping, as well as in the operations of dipping and 
placing, the proportion of defective pieces may still be too great 
to be borne. That, at all events, is the past experience of the 
potters who have worked with leadless glazes; and I feel 
assured that no firm of pottery manufacturers in this country is 
prepared to abandon leaded glazes for all their ordinary earthen- 
ware at the present time, and face the consequences. I cannot 
but consider that in this matter Profs. Thorpe and Oliver have 
been misled by the natural enthusiasm of those who have 
recently produced leadless glazes, and in their desire to put an 
end to the evils of lead-poisoning they have over-stated the 
no regulations at all, or have confined themselves to benevolent 
advice (see report, pp. 46-50), we have in this country adopted, 
on the initiative of the Home Office, and with the assent of 
manufacturers, regulations on the points named above, which | 
cannot fail to diminish the more serious evils complained of. 
Doubtless the pottery manufacturers will be grateful to Profs. 
Thorpe and Oliver for establishing this point. 
It was felt, however, that important and valuable as such 
regulations may be, they leave untouched the kernel of the whole 
question. The terms of reference contained in the letter from 
the Home Secretary inviting the co-operation of Prof. Thorpe 
put the matter very clearly : The Secretary of State desires to 
ascertain (1) how far the dangers may be diminished or removed 
by substituting for the carbonate of lead, ordinarily used, either 
(a) one or other less soluble compounds of lead, e.g. a silicate ; 
(4) ‘‘leadless” glaze ; (2) how far any substitutes found to be 
harmless or less dangerous than the carbonate, lend themselves 
to the varied practical requirements of the manufacturer ; (3) 
what other preventive measures can be adopted. 
The report sets forth ina clear, simple, and decided form the 
conclusions arrived at on these points. It furnishes an account 
of visits paid to various pottery works on the continent. 
Results are given of the analytical determination of the pro- 
portion of lead compounds in glazes collected from a number 
of potteries in this country. Valuable tables are also given as 
to the solubility of various lead compounds, and of certain 
pottery ‘‘fritts” and glazes containing lead, in dilute, hydro- 
chloric, and acetic acids; and. z¢er a/éa, we find that Prof. 
Thorpe has discovered in the course of his investigations a 
compound silicate containing 22 per cent. of lead oxide, which, 
he says, is insoluble in dilute acids. We are also furnished with 
the considerations and arguments on which the Professors have 
based their recommendations. 
The recommendations themselves are four in number, and 
may be summarised as follows :— 
(1) The prohibition of lead compounds entirely in the glazes 
used on seven-tenths of the wares produced in the potteries. 
(2) That in all other branches of the pottery industry lead 
shall only be used in the form of a fritted compound silicate. 
(3) That the use of raw lead—z.e. white lead—in glazes or 
colours should be absolutely prohibited. ; 
(4) That the employment of women and young persons as 
dippers, dippers’ assistants, ware cleaners after dippers, and 
glost placers should be prohibited in all factories where glazes 
containing lead continue to be used. 
That these conclusions, if carried into effect, would do away 
with lead-poisoning in the pottery industry, there can be no 
two opinions. That the first and fourth of them, if insisted 
on in the present state of our knowledge, would cause, not 
only a serious dislocation of the pottery industry, but the 
transference of some of it to our foreign rivals (who are, 
for the most part, under no restrictions whatever as to their 
use of lead compounds or female labour), there can also be 
little doubt. Even in view of such circumstances, the adoption 
of these conelusions might be considered advisable, if an 
impartial consideration of the facts stated in the report showed 
that no other conclusions would meet the case. It is necessary, 
therefore, to consider whether the conclusions arrived at by 
Profs. Thorpe and Oliver are justified by the information given 
in the report. It may be said at once that a careful consider- 
ation of the report leads one to the conclusion that they are not. 
The facts contained in the report may be summed up as 
follows :— 
(1) English potters, generally speaking, use glazes containing 
“raw,” z.e. “funfritted” white lead. This compound finds its 
way into the system, and being readily soluble in the gastric 
juice produces an excessive amount of lead-poisoning. 
(2) Women and young persons are stated to be more suscept- 
ible to lead-poisoning in this way than adult malés. The figures 
quoted are open to other interpretations. 
(3) Leadless glazes aré being tried by several manufacturers 
in this country on a limited scale. The results obtained so far 
may be described as satisfactory ; but that they have been tried 
on an adequate scale, and under widely varying conditions, 
there is not sufficient evidence to prove. 
(4) Certain foreign manufacturers, producing pottery similar 
to that produced in this country, have abandoned the use of 
*“raw ” white lead in their glazes. 
(5) The glazes stated in the report to be used by these | 
manufacturers contain as large a percentage of lead monoxide | 
| 
NO. 1540, VOL. 60] 
Mol f 
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