1910.] Overhead Electrical Discharges. 25 



Within the house, the wire was simply hooked on to 

 another wire, running the whole length of the house, and 

 supported by ebonite insulators attached to either door by 

 lengths of paraffined string running through holes in an 

 ebonite rod. This single wire was of comparatively small 

 diameter and acted as the discharge wire. 



The houses are arranged in groups of five, without walled 

 partitions separating them, and hence it was possible to run 

 the charge from house to house within the same block by 

 simply carrying a wire under the wooden frame supporting 

 the glass roof, the wire being passed through a long cylinder 

 of porous earthenware that was suspended freely from the 

 roof by means of paraffined string. 



Under these conditions the discharge was obtained, but 

 from the construction of the houses it is certain that a very 

 large percentage of the charge must be lost. 



Thus the hot-water pipes are raised well above the floor, 

 and the base of the plants may be described as being in the 

 "shade" of these iron pipes as regards effective discharge, 

 as the plants are not raised upon staging above the hot-water 

 pipes. . Cucumbers and tomatoes are the crops usually grown, 

 and while the tomatoes may obtain their fair share of the 

 charge, the cucumbers, in their attempt to obtain light, 

 spread their leaves and stems so close to the glass that they 

 run within the protection of uninsulated wires, placed near the 

 roof to afford them support, and to which their tendrils cling. 

 To such extent as they lie behind these wires they must be 

 very much out of the region of discharge, and it does not 

 seem to me surprising that the results for 1908 with 

 cucumbers grown in this manner show very little difference 

 that can be attributed to the current. And yet even in this 

 case the acceleration results are quite striking, as is shown 

 by the table appended of the cucumbers cut from five of the 

 houses in April, 1908. 



Another difficulty that has to be met in installation under 

 glass is the added risk of shock to those working amongst 

 the crops. Cultivation under forcing conditions involves 

 almost continuous attention being paid to the plants, 

 and as a consequence arrangements have to be made 

 to allow men to work amongst the crops without the- 



