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NOTES AND MEMOEANDA. 
Powell and Lealand's new § inch. — The 'Academy,' which oc- 
casionally has valuable microscopical notes, states that the new ^th. of 
Powell and Lealand is a decided advance in accuracy of correction, 
and if, as there is some reason to expect, the glass-makers can suc- 
ceed in producing a material rivalling the refracting powers of the 
diamond, still further progress would be within the reach of skilful 
optical artists. An aluminium glass is spoken of as likely to fulfil 
the requisite conditions. 
Glass riLl)y-tinted with Gold, seen with the Micro-spectroscope. 
— The writer of the microscopical paper above mentioned says that his 
attention has been called by Mr. Lettsom to the remarkable spectrum 
afforded by glass ruby-tinted with gold. In a slide prepared by him, 
kindly forwarded to us, we find the luminous part of the green and 
blue darkly clouded by a very thin slice of the glass while the red 
and violet portions of the spectrum remain clear. At night, with the 
micro-spectroscope and a paraffin lamp, the cloudy band has a peculiar 
red tint, well seen if the lamp is screened so that little light can 
reach the eye except what passes through the spectroscope. 
Microscopical Soiree at the British Association. — This is said 
by a contemporary to have been a very great success, and the Asso- 
ciation owes its hearty thanks to Messrs. W. Tedder and J. W. Morris, 
the secretaries respectively of the Bristol and Bath Microscopical 
Societies, and to the members of those societies. A bold idea was well 
carried out, viz. that of exhibiting chiefly living objects. The 110 
microscopes were arranged in classified divisions, devoted to Crustacea, 
Arachnidans, Insecta, marine and fresh-water fauna, ciliary action, 
vertebrate circulation, vegetable circulation, fertilization of flowers, 
Cryptogamia, micro-spectroscopes, &c. The idea of practically illus- 
trating Sir John Lubbock's ' Fertilization of Flowers by Insects ' was 
novel, and so far carried out as to give a vivid idea of the processes to 
those who were previously unfamiliar with them. The geological 
division included an exhibition of the perennial Eozoon canadense, 
which must be exhibited again and again to live down the hostility to 
its animal nature. Altogether the exhibition was a great evidence of 
scientific enthusiasm, which had led many ardent students to make 
special dredging and fishing expeditions both in inland and marine 
waters. 
Anatomical Micro-photographs. — At the meeting of the British 
Association, Mr. H. B. Brady, F.E.S., exhibited a series of photo- 
graphs, chiefly from physiological and pathological preparations, 
taken by a new and simple process devised by Mr. Hugh T. Bowman, 
of Newcastle. The apparatus was also shown, and described to consist 
of a simple mirror of spectrum metal placed at an angle of 45° in 
front of the eye-piece of the microscope, directed downwards. The 
image was received upon a collodion plate set in the frame of a 
