420 
PROCEEDINGS OF THE SOCIETY. 
tho volume embodied much practical information on the technical pro- 
cesses of photography ; whilst the chapters devoted to the description 
of the various methods of adjusting the Microscope and accessory appa- 
ratus required in the production of photomicrographs bore everywhere 
traces of Mr. Nelson’s co-operation, as frankly acknowledged by the 
author. It had struck him as somewhat strange that a work of this 
kind, addressed primarily to an American audience (for it was published 
by the Scovill and Adams Company, of New York) should contain so 
little reference to the employment of sunlight, the most powerful illumi- 
nation at the disposal of the microscopist for photomicrographic work, 
and so generally available in America. The use of the electric light 
was also dealt with very cursorily, though he was under the impression 
that great facilities were offered in America for its employment. The 
oxy-hydrogen light was explained in considerable detail, and some 
excellent examples of photomicrographs produced with it were given. 
Mr. May all also referred to the donation, by Messrs. Trainini Bros., 
opticians, of Brescia, of an early form of achromatic Microscope 
objective, constructed by the late Bernardino Marzoli, curator of the 
Physical Laboratory of the Lyceum of Brescia. He said the donation 
promised to be of historical interest ; he would therefore explain the 
circumstances of its arrival, and the data which gave it special interest. 
In collecting notes on the early history of the application of achromatism 
to the Microscope, he had found a reference to Marzoli’s achromatic 
objectives in Giovanni Santini’s ‘ Teorica degli Stromenti Ottici,’ 
published in Padua, 1828 (2 vols. 8vo). In vol. ii. p. 187, Santini 
mentioned Selligue’s then recent achromatic objectives as described in 
the French journals, and stated that Marzoli, of Brescia, had long 
preceded Selligue in the production of such objectives. Such a state- 
ment by Santini seemed to him to merit special attention, and he deter- 
mined to make inquiries at Brescia for any traces of Marzoli’s objectives. 
By the courtesy of Mr. Frederick Justen, a newly-elected Fellow of the 
Society, a communication of the particulars was made to the President of 
tho Athenmum of Brescia, who most kindly saw the Brothers Trainini, 
the grand-nephews of Marzoli, on the subject. These gentlemen replied, 
stating that Marzoli was an amateur optician ; that he had taken 
much interest in the application of achromatism to Microscopes ; that 
a paper of his on the subject had been summarized by the secretary of the 
Accademia di Scienze, of Brescia, and published in the Commentary for 
the year 1808 ; that he had exhibited his achromatic objectives at Milan 
in 1811, for which he had been awarded a silver medal under the autho- 
rity of the Istifuto Beale delle Scienze, of Milan ; that they possessed 
one of these objectives, which had been “ religiously preserved,” and 
they would send it to the Boyal Microscopical Society if it were thought 
acceptable. He (Mr. Mayall) replied to Messrs. Trainini, assuring 
them that such a donation would be much appreciated by the Society, 
and requesting them to furnish the fullest information regarding 
Marzoli’s actual work, and if possible send a copy of any official docu- 
ment that might exist to confirm the fact that he received a public 
recognition of his labours in connection with the production of achromatic 
objectives so early as 1811. Messrs. Trainini forwarded (1) the Processo 
