ture and flow fields, as indicated by equations (12)-( 14).The difference between the concentration andtemperature fields is dictated by the Lewis number, inother words, the T and C fields are identical only in thespecial case Le = 1. In addition to the expectedrelationship between Ra, and Nu (see also Fig. 2), Table2 shows that when Ra, is fixed the Sherwood numberconsistently increases as the Lewis number increases. Inother words, when the heat-transfer-driven flow isfixed, the concentration boundary layers becomeincreasingly thinner as Le increases.Table 3 summarizes the series of experimentsdesigned to document the effect ofbuoyancy ratio, N. Abirds-eye view of the trend revealed by these numericalresults is conveyed by Fig. 3. The most striking featureof the N effect is the suppression of convection as a