NATIONAL PHYSICAL LABORATORY. 
of Munitions. This work had previously been done solely at the 
Woolwich Arsenal, and gauges had been supplied by a few outside 
firms, or were made in the arsenal itself. With the demand for muni- 
tions in quite unprecedented quantities, came the need for a correspond- 
ing production of gauges, with which the various shells, fuzes, &c., 
should be tested before acceptance by the Ministry of Munitions. Con- 
tracts for gauges were let to many firms, who had not tried that work 
before, any likely firms being used for this purpose. Quite a number 
of these, sooner or later, turned out good work, the most successful as a 
class being those who had had experience in the construction of internal 
combustion engines. In this matter, however, and in particular in the 
production of screw gauges, most valuable work was done by the staff 
of the National Physical Laboratory Meteorology Department, who col- 
laborated with gauge-makers in the solution of their difficulties. This 
personal contact contributed largely to the success of various firms, who 
would certainly have become dispirited by early failures had red-tape 
measures been adopted. The great advantages offered to mamufac- 
turers of accurate machines, &c., is even now hardly realized by them, 
and it is to be hoped that the contact between manufacturers and the 
Laboratory will be maintained. Many special measuring machines 
were devised by members of the staff for the measurement of munition 
gauges, but there is not space at present to describe thesé. The arsenal 
branch of the Defence Department has acquired a set of the machines 
for the measurement of screw gauges. 
One of the most important of these machines is a projection lantern 
capable ‘of giving a picture 4 feet square without sensible distortion, 
the magnification heing 50 diameters. «This is most useful in the 
examination-of screw gauges (for which purpose it was designed), but 
its usefulnéss extends over a far wider range, and it is applicable to 
many kinds of fine tool work. 
Important researches have been conducted on the subject of slip 
(Johansson) -gauges, and a method of producing gauges of this kind 
has been elaborated. A new design of measuring machine, capable of 
comparing slip gauges toa high degree of accuracy, has also been 
designed. : tei aa 
The Electrotechnies division of the Department of Electricity 
(under Mr. F. E. Smith) undertakes tests on all kinds of electric 
machines, cables,.and the like. The calibration of meters is an im- 
portant part of its routine work. New methods of the measurement 
of power by electrostatic methods have been devised by members of the 
staff, and are in regular operation. The manufacture of manganin, 
hitherto a German monopoly, has been investigated by the staff of this — 
division, and satisfactory processes have been devised. Photometry is 
also dealt with by this division. 45 
The work of the Engineering Department comprises four main 
divisions, devoted, respectively, to the testing of materials, the testing 
and design of engineering apparatus, appliances, and machines, 
the testing and investigation of road materials and aeronautics. 
Limitations. of space do not allow of more than the briefest 
description of the various activities coming under the above 
heads. Very valuable information has been obtained concerning 
C.5690.—3 ' 209 " : 
