THE NATIONAL PHYSICAL LABORATORY 293 



Civil Engineers, who have contributed generously towards the support of the 

 work of the Laboratory. A research on wind-pressure was at once com- 

 menced, directed to the determination of a method of estimating the wind- 

 pressure on large structures from the results of experiments on small models 

 in the Laboratory. An account of the earlier experiments on models in an 

 air channel was published in 1903, and this work was followed by the in- 

 vestigation of the wind-pressure on larger surfaces in the open. The next 

 step was to determine what relation the maximum pressure intensity in a given 

 period of time over a considerable area, such as that of a large engineering 

 structure, bears to the maximum intensity occurring at a single point of the 

 area. The last stage of this research, to determine the effect on this relation 

 of the more or less exposed character of the site, has now been entered upon. 



A second extensive research has been in progress in the Engineering 

 Department to determine the behaviour of materials under repetition of 

 stresses of various kinds. Papers published in the course of this research 

 relate to the construction of an alternating stress-testing machine, the 

 resistance of iron and steel to reversals of direct stress, a new fatigue test for 

 iron and steel, a repeated impact testing machine and the resistance of 

 materials to impact, and other work of a similar character. 



Research in Aeronautics was commenced in 1909, and considerable progress 

 has been made in the study of the forces due to the wind on airships and 

 aeroplanes. 



In the Metallurgy Division the work initiated by Sir William Roberts- Austen 

 was continued at the Laboratory for the Alloys Research Committee of the 

 Institution of Mechanical Engineers and with the support of that Institu- 

 tion. The several reports made to this Committee deal respectively with 

 iron-nickel-manganese-carbon alloys, alloys of aluminium and copper, alloys 

 of copper aluminium and manganese, and alloys of aluminium and zinc. 

 A large number of other papers on metallurgical subjects have been published. 



The investigations on ship-models in the Tank Department were commenced 

 in 1911, and this work will in future constitute an important branch of the 

 research-work carried out by the Laboratory. 



During the period in which the Kew Observatory was a Department of the 

 National Physical Laboratory, the Superintendent, Dr. Charles Chree, F.R.S., 

 published a valuable series of memoirs reducing and discussing the magnetic 

 observations recorded at the Observatory, as well as magnetic observations 

 taken at Falmouth, and the magnetic and meteorological records obtained 

 by expeditions to the Antarctic regions. (See p. 301.) 



In the year 1908 the conditions regulating the character of the test-work 

 undertaken by the Laboratory for manufacturers and other private bodies were 

 further defined by a Committee appointed by the Treasury, of which the 

 Right Hon. Gerald W. Balfour acted as Chairman. 



The total capital expenditure of the Laboratory up to December 31, 1911, 



