104 
NATURE 
[MarcH 25, 1915 

The proportion of definite replies coming in at once 
has been smaller than in the case of the public schools 
from the fact that various committees have had to be 
consulted before definite promises could be given, but 
the replies which have been received have been quite 
satisfactory—of the definite replies received about 72 
per cent. are sympathetic, and promises are given to 
purchase only British-made apparatus as requested, 
subject in many cases to the proviso that the increased 
cost is not prohibitive. 
A considerable number of the replies, while gener- 
ally sympathetic, give no guarantee, the reason being 
in most cases that the matter rests with a higher 
authority, such as a county council, or board of 
governors, from whom no definite reply had been 
obtained. Some authorities, also, while sympathetic, 
do not feel able to bind their successors, and one 
authority suggests that only the purchase of German 
and Austrian apparatus should be barred. 
The endeavour to obtain the value of the apparatus 
used in such institutions has not resulted in any very 
precise information, but from the facts before the com- 
mittee it is clear that the value of such apparatus 
must at least run to some thousands of pounds. 
(B) Types and Sizes of Apparatus most in Demand. 
Inquiries as to the principal types and sizes of 
apparatus most generally used have been made on 
behalf of the Joint Committee from public schools and 
technical schools. It was felt by the Joint Committee 
that this information would be of considerable value 
to glass-makers, as there is a very strong feeling 
among those concerned with the chemical apparatus 
trade that at the present time flasks, beakers, basins, 
etc., are supplied in an unnecessarily large variety of 
shapes and sizes. 
Judging from the replies received from the institu- 
tions above referred to, the following represent the 
apparatus most in demand :— 
Test Tuses.—6 in.x® in., 2 in.x3 in., and, in 
smaller quantities, 6 in.x1r im., 5 in.xg in., and 
2 in. x} in. 
Beakers.—Squat form, lipped, 200 c.c., 300 ©.C., 
and, in smaller quantities, 150 C.c., 500 C.C., 1000 C.C. 
Brakers.—High form, in the same sizes as above, 
but in smaller quantities. 
Frasks.—Flat bottom, 100 ¢.c., 250 C.C., 500 C.C., 
and, in smaller quantities, 1000 c¢.c., 1500 C.C., 
2000 C.C. 
Fiasks.—Round bottom, 250 ¢.c., 500 c.c. 
TuBULATED RETORTS.—I50 C.C. 
FUNNELS.—6:5 cm. 
DISTILLING FLASKS.—I00 C.C., 250 C.C., 500 C.C. 
EvaporaTInG DISHES.—50 ©€.C., I00 C.C., 200 C.C., 
and, in smaller quantities, 1000 c.c., and 2000 c.c. 
CRUCIBLES.—15 c.c. and 25 c.c. 
In conclusion, the Joint Committee desires to ex- 
press its strong conviction that every effort should 
be made to facilitate and encourage the manufacture 
of glass and porcelain apparatus in the United King- 
dom. It therefore urges the advisability of asking 
the Board of Trade to watch the new industry, and, if 
necessity should arise, to use its endeavours to modify 
any restrictions at present existing which may be 
detrimental to the carrying on and extension of the 
industry. 
(2) THe ManuractureE oF OpticaL INSTRUMENTS AND 
Matters RELATING THERETO. 
NECESSITY FOR ACTION. 
The British Science Guild, having inquired care- 
fully, by means of a strong and representative expert 
committee, into the effect of the outbreak of hostili- 
ties on matters of national importance connected with 
the manufacture of optical instruments in the country 
NO. 2369, VOL. 95]| 

generally, submits this report to the Government, and 
in doing so emphasises the pressing urgency of the 
subjects referred to. 
Supply of Glass. (a) The General Case. 
(1) In the first place the inquiry referred to was 
directed to the consequences of the sudden stoppage 
of the supply of German optical glass on which this 
country had increasingly relied for many recent years. 
A letter of inquiry asking for information on six 
| specific points was addressed to representative firms 
in the optical trade. The results of these inquiries 
has been such as to satisfy the guild that the supply 
of optical glass available for the manufacture of tele- 
scopes, binoculars, range-finders, and other service 
instruments is sufficient for the purpose. Under this 
head there seems to be no call for any special effort to 
improve upon existing conditions, though the supply 
of English glass has not always been adequate in 
quantity, and delays have been experienced in obtain- 
ing quick delivery. 
The representative of Messrs. Chance Bros., who 
was a member of the Technical Committee referred 
to above, has assured the committee that since the 
outbreak of hostilities the firm has considerably in- 
creased (in fact, quadrupled) the capacity of its plant 
for the manufacture of optical glass, and is fully pre- 
pared to extend this plant still further. 
(b) Photography and Micrography. 
(2) With regard to the manufacture of photographic 
and microscopic lenses the case stands otherwise. The 
requirements of the manufacturing trade in these 
respects are not definitely standardised as in the case 
of the instruments already referred to. To facilitate 
new and important developments it is necessary that 
the lens manufacturer should have recourse to a 
greater variety of glasses than are, in fact, manu- 
factured at the present time in this country. It is 
further necessary that larger stocks should be held 
than is the custom at the present time of the various 
glasses produced. The guild, therefore, is of opinion 
that serious inconvenience is certain to result to the 
manufacturing trade if the supply of German glass is 
cut off for any considerable length of time. The 
amount of glass demanded, especially for photographic 
purposes, is very considerable, and the guild is of 
opinion that the attention of the authorities might use- 
fully be directed to this opportunity for a considerable 
development of British glass manufacture in this 
direction. One difficulty the guild understands to be 
the defective supply of pure barium compounds. 
(c) Variety of Glass Obtainable Inadequate. 
(3) From a wider point of view and more generally, 
the variety of English glasses offered is not sufficient 
for all the requirements of optical instrument-makers, 
especially for the more recently developed and impor- 
tant optical designs. Thus, whilst the leading Eng- 
lish firm listed only twenty to thirty types of glass, 
the leading German firm listed about seventy types, 
every one stocked. Barium glass of high refraction 
and low dispersion, i.e. having a high value of the 
‘“‘anti-dispersion’” coefficient, is reported as specially 
difficult to obtain in England. 
Research. 
(4) The desirability of the provision of facilities for 
research upon the manufacture of optical glass has 
been carefully considered and has been found to be a 
difficult question. From the evidence submitted it 
appears that if one special object of research could be 
attained the result wouid be highly advantageous. 
This object is the discovery of a refractory lining of 
: the melting “ pot’? which would resist the action, at 
