Patterson and Cawood

Parker and Hottel, 254 Patten, 216, 238 Patten and Gallagher, 236, 242 Patterson and Cawood, 71 Pauthenier et al, 188 Pearson see Bosanquet) Perrott and Kinney, 47 Pien see Kalinski)... 

The earliest of these graticules by Patterson and Cawood has 10 globes and circles ranging in diameter from 0.6 to 2.5 pm when used with a +2 mm lOOx objective-eyepiece combination and is suitable for thermal precipitator work [69]. 

The technique of pressure balancing used so effectively for measuring gas densities and determining molecular weights by Cawood and Patterson (74), Leadbeater and Whytlaw-Gray (75) and Lambert and Phillips (76) has been applied to surface studies but is limited in that the surface study must be made at the pressure required for balancing. However, it is a simple effective and remarkably precise technique for weight compensation in studies where small variations in the pressure of the gas or vapor is not of critical importance. 

Figure 14 Diagram of the modified Patterson-Cawood globe and circle graticule used for counting and sizing particles. (From Ref. 7, with permission of the Journal...

Whytlaw-Gray, R., Cawood, W., and Patterson. H, S. (1936) Disperse Systems in Cases Dust, Smoke and Fog, A General Discussion of the Faraday Society, April 1936. 

The microbalance is used to determine pairs of pressures at which two gases oxygen and nitrous oxide produce the same buoyancy and consequently have equal densities. Pairs of pressures of oxygen and p Q of nitrous oxide were thus obtained at 21 C by Cawood and Patterson (Phil. Trans. A 1936, 236, 92) and are given in table 1. 

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