320 PROCEEDINGS Ol' SOCIETIES. 



MicnoscopiCAL 801HEE, GIVEN- TO THE Membeks oe the 

 British Association at the Meeting at Manchestee, 

 r)fh September, 1861. 



The local executive committee decided upon giving a series of 

 aoirees to the members of the British Association during their 

 meeting at Manchester, and the 3''ree Trade llaU was engaged for 

 the purpose ; a permanent exhibition for tlie week was arranged, 

 consisting of glazed cases containing specimens of geology, botany, 

 and zoology, uaeclianieal models, philosophical instruments, Indian 

 iabrics, local manufactures, &c. ; various drawings and diagrams, 

 and a choice collection of large paintings, surrounded the walls of 

 the gallery. Tt Avas determined that three principal soirees should 

 be given, and, in addition to the above exhibition, one evening 

 sliould be devoted principally to microscopical objects, one to tele- 

 graphic apparatus, and another to olijects of natural history. The 

 special featiire for tlie evening of Thursday, September oth, was 

 an exhibition of microscopes, under the management of a sub- 

 committee of the microscopical section of the local Literary and 

 Philosophical Society, assisted by Dr. T. Alcock and Dr. William 

 Roberta. 



Tables for the mici-oscopes Avere arranged in three of the princi- 

 pal rooms in the building ; two tables, each sixty feet long, were 

 placed along the centre of the large hall ; two tables, each twenty- 

 five feet long, under the platfonn ; and a curved table, fifty feet 

 long, across the end of the gallery. In the assembly and drawing 

 rooms upwards of four hundred feet of front table-space was pro- 

 vided, and four tables, each sixteen feet long, across the larger of 

 the two rooms. Altogether, one hundred and fifty microscopes, 

 most of them first-class instruments, were lent for the occasion ; 

 upwards of ninety private instruments, of which eighteen were of 

 recent binocular construction, were contributed by-gentlemen resi- 

 dent in the city and neighbourhood; the remainder, of which about 

 thirty were binocular, were exhibited by makers of microscopes in 

 London and the provinces. 



In order to diminish the risk of damage to objects and instru- 

 ments, it was determined by the sub-committee to show, for the 

 most part, objects with low powers, and, to avoid loss of time and 

 confusion in changing objects, that most of the microscopes should 

 exhibit only one specimen during the evening ; it was considered 

 that if one minute were devoted to each object, two hours and a 

 half would be required to examine the hundred and fifty micro- 

 scoi)es collected together. 



in the large hall sixty microscopes were arranged to exhibit 

 a series of objects carefully selected from the various departments 

 of nature. The series commenced with a specimen of granite, 

 tlie oldest of the rocks, shown by polarized light ; the scale was 

 gradually ascended by specimens of quartz containing gold, 



