Neiv Engine for RidiiKj. 45- 



tional work vipon the niacluue, and also partly in that the under- 

 taking Avas later recognised as a piece of " Research Work " under 

 the regulations governing University Research Scholarships. The 

 latter adjustment served to bring the work directly under the 

 notice and control of the Professor of Physics, Dr. T. R. Lyle, 

 F.R.S., to whom it was arranged that I should report from time to 

 time. Tliis served to make available additional mechanical facili- 

 ties, and led to a transference of my services and work to the 

 Department of Physics. 



Preliminapy Outline of the Design of tlie Machine. 



It is desirable, before describing the more important parts of the 

 machine, to outline its essential features. A fuller description of 

 certain parts is also desirable, as published descriptions of similar 

 machines frequently lack constructional details. 



Even Professor Rowland's article, on the grinding of a pre- 

 cision screw, omits reference to impoitant working details; 

 while similar omissions occur in the published description of 

 his ruling machine, issued at a much later date. Thus one 

 frequently fails to find the information sorely needed when entering 

 upon a 'similar undertaking. The omission of information, with 

 respect to the working routine of these undertakings, may frequently 

 mean the difference between success and failure, or, in any case, 

 great lose of time and labour on the part of those who attempt 

 similar work. Occasionally, even negative experiences are not 

 without value, and are worth recording. 



In the following preliminary description of the completed 

 machine, reference to the plates and photographs, particularly 

 Plates VI. to XA^II., will l^e advantageous. For example, Plate VI. is 

 a plan of the complete Engine drawn to scale. The various parts 

 are numbered, and their general purpose and relationships are 

 indicated in the descriptive index. 



The bed of the machine, marked A, of cast iron, is a hollovy 

 rectangular oblong box, with several internal cross webs for increas- 

 ing its rigidity. Plate VII., an end view photograph of the 

 machine, shows the external outline of the bed. Externally, the bed 

 has been accurately machined throughout; the top surface and one 

 edge have also been ground true. This form of bed is very rigid 

 in proportion to its mass, and is, moreover, not unwieldy to handle 

 or complicated in outline; its weight, apart from any attachments,, 

 is under 70 lbs. 



