100 REPORT OF NATIONAL MUSEUM, 1923. 



the industrial world. As a result, the divisions are constantly in com- 

 petition with industrial concerns in securing and maintaining their 

 staff, but on account of the fact that the remuneration which the 

 divisions can offer is less than that offered by industrial concerns, 

 it is extremely difficult, in fact, impossible to hold experienced men. 

 The net result is that the personnel is constantly changing, a condi- 

 tion which does not tend to produce the best results. 



In addition to maintaining the collections a considerable amount 

 of new work was produced by the preparators and aid. This in- 

 cluded the completion of the model showing the production of manu- 

 factured gas, a model 30 inches wide and 8 feet long. The processes 

 shown include the manufacture of coal gas and the manufacture of 

 carburetted water gas. As shown in the model the product of 

 these two processes is collected in a large gas holder from which it is 

 withdrawn through pipe lines and transmitted to the home. 



In the workshop of the division of mechanical technologfy a 

 model of the aircraft designed by Sir George Cayley, of England, 

 in 1843, was constructed and placed on exhibition. This model is 

 made to scale and is one-fourth the size of the original machine 

 designed by Cayley. Its particular feature is that of having four 

 vertically revolving propellers mounted in pairs one above the other 

 on each side of a four-wheeled chassis. The propellers are made up 

 of nine blades each and are so constructed that when the aircraft 

 reaches a desired elevation the blades automatically flatten out and 

 act as planing surfaces or wings. In principle, Cayley's design of 

 aircraft is to-day referred to as a heliocopter. 



There was also made in the division workshop and placed on 

 exhibition a series of 35 models illustrating some mechanical element 

 or device. These models illustrate, for instance, the various types 

 of lever actions; methods of power transmission; methods of pro- 

 ducing various types of motion by mechanical action; pulley blocks 

 and combinations of pulleys, etc. Considerable use is made of these 

 models by Museum visitors, visiting schools, inventors, and others 

 having mechanical problems to solve. 



EESBARCH. 



Considered broadly, all of the model construction work of the 

 divisions requires a considerable amount of preliminary investiga- 

 tion and study, so that it may be said that research investigations 

 for the benefit of the Museum were continuously under way. As an 

 example, the definite data as to Cayley's aircraft are extremelj^ 

 meagre and widely scattered. Furthermore, the data which were 

 brought to light were found to be rather incomplete and considerable 

 research work was required to secure the necessary information for 

 the construction of a model. Again, prior to starting the construc- 

 tion of the model visualizing the land pebble phosphate industry, it 



