70 SCIENTIFIC SURVEY OF LEICESTER AND DISTRICT 
called upon Leicester for the installation of their heating and ventilation 
equipment. The quarrying, boot and shoe and woodworking industries 
require, of course, dust-extracting plant, and the satisfaction of this need 
has consequently become an associated branch of the work of specialists 
in heating and ventilation. Dust-extracting plant made in Leicester has 
been installed in industrial houses all over the world. 
An industry in which Leicester stands as a pioneer, and one which has 
become peculiar to the town, is the manufacture of scientific and optical 
instruments and of photographic lenses. When it is stated that a 
Leicester-made lens has to fit a standard gauge to within a half-millionth 
part of an inch, the degree of precision in its manufacture will be realised. 
Some of the most accurate machines in the world must be those engaged 
in the production of optical instruments and measuring machines for 
which the city is famous. In view of the extraordinary degree of accuracy 
in screw-threads necessary in the manufacture of optical instruments, 
extensive research was an essential preliminary to manufacture. This 
research proved invaluable in the fixing of the British Standard Specifica- 
tion for screw-threads, and it can be truly said that many of our present 
standards emanated from Leicester. In addition, the majority of films 
exhibited in British cinemas are both produced and projected through 
lenses made in Leicester, while the greater proportion of projectors at 
Hollywood are equipped with these same Cooke lenses. 
The largest electric turret clock in the world, that in the tower of the 
Singer building at Glasgow, was constructed by a Leicester firm which 
has specialised in bells, clocks and other electrical devices for sixty years. 
‘ Pul-syn-etic ’ electric clocks are met with in every country in the world. 
Delhi is timed by ‘ Pul-syn-etic,’ with five master clocks and 400 auxiliaries ; 
while the new Parliament building at Belfast is equipped with 137 of these 
clocks. Electro-motor chiming gears for use in conjunction with the 
‘ Pul-syn-etic ’ system constitute a further activity of the same firm, while 
travellers by Cunard and other lines will set their watches and take their 
meals by clocks made in Leicester. Thus can Leicester engineers claim 
to keep the world punctual. 
There may be something coincidental in the fact that the multifarious 
industries of the city and county seem to agree upon the desirability of 
producing especially those classes of goods which the ultimate consumer 
insists upon receiving in cardboard boxes. Leicester, of course, makes 
her own boxes, and her many box-makers are, moreover, well served by 
local engineering firms engaged in the manufacture of highly ingenious 
machinery for that purpose. Box-making machinery from Leicester is 
despatched to all parts of the country, and a very satisfactory export trade 
is maintained. 
Leicester possesses the largest typewriter factory in the British Empire. 
The modern typewriter, consisting as it does of some 2,000 parts, is a 
triumph of engineering skill, and one learns with interest that the Leicester 
firm of manufacturers permits a margin of error of only one-thousandth 
part of an inch. 
The cordial relations which have long existed between the Engineering 
Department of the College of Technology and the engineers of Leicester 
