52 



One of the chief difficulties is that due to vibration ; if much traffic 

 pass the house, exposures are best made late at night. Ortho- 

 chromatic plates should be used because of the more correct colour 

 values obtained and also for the reason that sharper results are got 

 with the objectives in general use, which are not corrected for 

 photography. 



The first of the summer excursions devoted ex- 

 o ograp ic clusively to photography took place on May 21st, 



when five members went in the morning to Corfe 

 Castle. The party was conducted by the Chairman. It was a dull 

 day but a few good negatives were secured in spite of the weather, 

 which was hardly suitable either for record or pictorial work. An 

 excursion to Brockenhurst and Boldre was arranged for June nth, 

 but owing to bad weather it was postponed. A combined Archaeo- 

 logical and Photographical excursion took place to these parts of 

 the Forest, under tde conductorship of G. Brownen, Esq., f.c.s., on 

 Aug. 31st. 



The Portfolio has continued to circulate throughout the summer 

 months and will do so in future. It affords much scope for mutual 

 discussion and improvement. At the time of writing it possesses 17 

 contributors. Any other member who would like to join is requested 

 to apply to the Chairman, at Ditton Lodge, Stourwood, Bourne- 

 mouth. A subscription of one shilling per annum is charged. 



PQgstral Section- 



Chairman: Hubert Painter, Esq., B.Sc, F.C.S. 



During the Society's year 1909-1910, five meetings of the 

 Physical Section were held at the Society's rooms and a largely 

 attended excursion took place in ]une. The Chairman gave a 

 lecture at a General Meeting of the Society on " The Chemical 

 Analysis of Solutions." A report of this appears on another page. 



_ . The first meeting of the section was held on Nov. 

 : 6th, when Dr. Mahomed gave a lecture on the 



ec rici y. above subject. The lecturer described the methods 

 and some of the results of his experiments on the variations of the 

 electrical potential in the atmosphere, prefacing his remarks by a 

 brief historical sketch of the subject, and by a summary of the 

 results obtained by various observers. Irregular and capricious as 

 the variations of atmospheric potential appear to be, distinct 

 evidence has been obtained of an annual and a diurnal cycle of 

 changes. There are two daily maxima which appear to be 

 dependent upon, although they do not coincide with, the times of 

 sunrise and sunset. The winter readings are higher than those 

 obtained in summer. The lecturer exhibited the electrometer with 

 which his observations nad been made and various diagrams were 



