810 REroKT— 1S98. 



near the roots of the plants. The results obtained with this Instrument, as given 

 in the French journals, were so remarkable, that I was very desirous of making a 

 trial in Clifton. Accordingly, in the early spring, M. Pinot de Moira, who is an 

 excellent amateur gardener as well as a careful experimenter, put up one in his 

 garden on Clifton Ilill. Potatoes, beans, peas, &'c., were grown near the wires and 

 in other parts of the garden. An increased ellect was distinctly observed in all 

 cases, thus contirmiug in some measure the results of the French experimenters. 

 It is, however, much to be desired that further and continuous experiments should 

 1)6 carried out. 



The theories to account for the action were then considered. 



6. Experiments with the Brush Discharge. 

 By E. H. Cook, D.Sc. Lond., Clifton Lahoratoi-y, Bristol. 



7. The Ancient Standard Weights and Measures of the 

 City of Bristol. By W. R. Barker. 



This group of Standard Weights and Measures forms an interesting link 

 with the past history of the city at various stages. The apparent rarity of 

 local standards of this kind was referred to and accounted for. Three periods 

 were recognised in which wholesale reforms were introduced by tlie issue of 

 fresh standards — Henry VII., Elizabeth, George IV. (Imperial System). Each of 

 these three issues is represented by one or more specimens in the collection. As 

 circumstances required, or sovereigns succeeded to the throne, intermediate 

 standards were issued, or the old ones were adopted under the new reign, so that, 

 in addition to those mentioned above, there are in this collection other standards 

 authorised under six other sovereigns, the whole embracing the long period from 

 1495 to 1S24. In all there are eighteen measures of capacity, two standard yard 

 measures, and thirteen weights. The marks, dates, and other peculiarities of each 

 were considered chronologically. 



8. Some Preliminary Experiments on the Luminosity produced by 

 striking Sugar. By J. Burke, M.A. 



The experiments show that the appearance of the flash produced when two 

 lumps of sugar are struck is independent of the gas in which the impact occurs ; 

 for instance, the effect is the same both in colour and intensity whether the spark, 

 if we might so call it, takes place in air or coal gas, and moreover is independent 

 of the pressure of the gas. The experiments have also been tried in water with 

 similar results. The spectrum of the flash is continuous, and contiiu-d to the more 

 refrangible end of the visible spectrum ; which seems to show that the luminosity 

 cannot be due to the particles of sugar on the impinged surface becoming white hot ; 

 but that the effect is probably due to some change in the configuration of the 

 crystals. The fact that the surrounding medium in wliich the spark occurs does 

 not alter the luminosity either in colour or intensity, seems to show that chemical 

 action with the surrounding medium does not take part in the production of the 

 light. An almost continuous luminosity can be produced by striking r.apidly the 

 circumference of a rotating wheel of sugar. The effect is very much greater when the 

 wheel is struck while it is rotating than when it is at rest ; but the mere rubbing 

 of the surface, whilst rotating, does not give rise to a very marked effect. The 

 sugar wears out very lapidly, and in order to keep the image of the spark on the 

 slit of the spectroscope the whole apparatus is moved slowly at the rate of about 

 2 inches an hour, by which means the luminosity always takes place along the axis 

 of the collimator. 



