PROCEEDINGS OF THE SOCIETY. 113 



small carbons, otherwise the arc tends to form at the back and away 

 from the direction in which the sonrce of light is needed. Tlie par- 

 ticnlar feature of the lamp now described is, that there is an appliance 

 for observing the extent to which the carbons are l)eing consumed, so 

 determining- when the real necessity arises for adjusting the length 

 of the arc. The lamp is of the hand -feed pattern, but in the majority 

 of such lamps with which he was familar, there is no method of observing 

 the condition of the arc other than by looking at it through darkened 

 glass. In the one shown, a small pinhole cajnera is mounted in such a 

 position that the arc can be directly observed ; the image of the arc itself 

 and of the ends of the carbons is projected on to the little ground glass 

 screen at the end of the pinhole camera. It is therefore only necessary 

 to look at this at intervals, say every two minutes, and to adjust the arc 

 as required. In actual practice he has found this arrangement to work 

 very satisfactorily indeed, as one can observe the image from a distance of 

 two or three feet away. He might say that this attachment is not novel, 

 as some years ago he described the same method applied to another type 

 of arc lamp, but for some reason that he was unable to determine it was 

 not taken up very generally, possibly because the feeding mechanism of 

 the lamp itself left something to be desired. 



These small arc lamps are now coming into such general use that he 

 ventured to think a method of directly observing the arc and for seeing 

 exactly when the necessity arises for its adjustment might not be without 

 service. 



Mr. Shillington Scales said he thought Mr. Barnard had made a 

 useful addition to this small arc-lamp, which was, he thought, one of 

 the best small arc-lamps he knew. The great disadvantage of the usual 

 type of this lamp was, as Mr. Barnard had said, the ready flaring of 

 the carbons, and once they flared the lamp quickly went out, so that 

 the new arrangement would enable one to judge the condition of the 

 light, and should be a great success. The only criticism which occurred 

 to him to offer was that he thought though the hood over the arc was 

 necessary, the parallelizing lens with which it was fitted, being a simple 

 uncorrected double-convex lens, was unsuitable for use with modern 

 highly corrected photo-micrographic condensers, such as the Conrady 

 system, and should be discarded. 



Mr. Barnard demonstrated that this difficulty had been foreseen, 

 and care taken to obviate it. 



The thanks of the Society were accorded to Mr. Barnard for his 

 interesting exhibit. 



Mr. Enock gave a lantern demonstration on " Insect Intelligence." 

 In his preliminary remarks Mr. Enock said that those who had studied 

 insect life for any length of time could not fail to have come across a 

 number of facts which really seemed to show that insects had intelli- 

 gence, and that of a high order. Lord Avebury had made remarks to 

 the effect that insects did possess, in a high degree, a sort of conscious 

 knowledge — certainly of their environment, especially in regard to 

 colour and markings. Whether this fact should be attributed to in- 

 telligence, instinct, or heredity must, however, be left to the individual 



Feb. 19tK 191S I 



