202 



" Proceedings of the Geologists' Association " From the Society. 

 '•Report of the EaHng Natural Science) 

 and Microscopical Society ... ...i 



Messrs. Swift exhibited a microscope on their four-legged 

 tripod model, but made of aluminium throughout, with the 

 exception of the rack work, screws, and wearing surfaces, these 

 latter being of steel, or faced with thin steel plates. All the 

 fittings, as eyepieces, sub-stage condenser, etc., were also of 

 aluminium, including the entire mount of the objective shown, 

 which Messrs. Swift believed was one of the first so constructed. 

 The President thought the use of aluminium for the objective 

 mount was greatly to be commended, as it would be a great 

 saving of strain on the fine adjustment, in some forms at least. 



Mr. Karop believed that one drawback to the use of aluminium 

 was that it was a very expensive metal to w^ork — the screws and 

 racks also had to be made of some harder metal. He thought 

 this difficulty might be met to some extent by making an alloy 

 of aluminium with some other metal which w^ould give it greater 

 hardness, while retaining some of the advantages of lightness. 



Mr. M. Swift said this could no doubt be done, but as soon as 

 they began to get harder alloys they got them heavier. 



Mr. Michael said it was easy to make an alloy of aluminium, 

 which was an exceedingly hard metal, but it w^as not exactly a 

 tough metal, at least so he found some years ago when he was 

 considering the possibility of making a microscope of this kind. 

 He thought, however, that the great value of this light weight 

 was where they wanted a travelling microscope — for it did not 

 much matter in the case of one which was to be used at home ; 

 but if there were to be steel parts introduced, were there any 

 means taken to prevent these from rusting ? 



Mr. M. Swift said the working parts were always lubricated 

 with oil, and this was found suflScient to prevent rust. He 

 might also say that when Mr. Michael approached them some 

 years ago on this subject, the aluminium which they were then 

 able to get was much more difficult to work than the kind they 

 were able to obtain now. 



The thanks of the meeting were voted to Mr. Swift for his 

 exhibit. 



Mr. Schroeder read a paper in which he described a new form 



