336 
TABLE II. 
Fatty acids 
Min. perc. 
Mol. Specific | Log. mol. 
Terms sr. pein’ weight smell int. smell int. - 6 
Formic acid 25 510-6 46 / 1.8.106 0.26 
Acetic acid 5.10—6 60 12.0.106 | 1.08 
Propionic acid 0.05.10—6 74 1480. 106 3.11 
Butyric acid 0.001.10 6 88 88000. 106 4.94 
Valerianic acid 0.01.10—6 102 10200. 106 4.01 
Caproic acid 0.04.10—6 116 2900. 106 3.46 
Oenanth acid 0.3.10 6 130 430. 106 2.63 
Caprylic acid 0.05. 10—6 144 2880. 106 3.46 
distance of the vertical nozzle, no charge will be generated *). An 
equal number of positive and negative nuclei splash against the dise 
and the algebraic sum of the charges is 0. On increasing the distance 
between the dise and the nozzle. while remaining well-insulated, the 
positive charge soon manifests itself, then gradually increases, until 
it reaches a maximum at a certain optimum. Later on it diminishes 
again, till it is reduced to zero, at a distance sharply defined for 
every substance. At this juncture we may say that all positive drops, 
produced in excess bv the cloud, are present in or drop down from 
a cone whose vertex is the nozzle of the spraying tube and whose 
base is constituted by the part of the dise moistened by the ctoud. 
The original negative nuclei, generated likewise by the cloud, are lost. 
As soon as the spraying has become fairly continuous we may 
assume that on this side of the disc, placed at the critical distance, 
the number of positive drops that descend is equal to that of negative 
ones that disperse in the surrounding air, while moreover an equal 
number of either sign dash against the base of the cone. At some 
spots an excess of positive droplets is present in the cone e.g. on a 
small dise, when placed at a shorter distance. Besides this, continually 
some fall down. If we were sure to catch up all the falling droplets 
and to determine their aggregate weight, we should possess a simple 
means to estimate the charge of an odorous cloud. J. C. Pomeroy’, 
has availed himself of this artifice to detect the faint charge imparted 
1) With an earthed sprayer pure water yields no charge, while with a sprayer 
insulated by amber it electrifies small discs. 
2) J. C. Pomeroy, Phys. Rev. vol. 27, p. 492, 1908. 
