The Presidc7iVs Address. 
37 
art, constructed for himself a camera box, travelling arrange- 
ments for micro-photographs, and with a good achromatic 
lens, manufactured by E^oss, set to work with his usual per- 
severance and industry to take the portraits of all his relatives 
and friends, scientific or not, the liberal distribution of which 
among his large circle of acquaintances afforded him un- 
alloyed pleasure. The Society's museum is enriched by his 
liberality with micro-photographs of some sixteen of its 
members. 
Several other short notices from our deceased member 
have also appeared in the pages of the ' Quarterly Journal of 
Microscopical Science,' as " On thin glass Covers" (vol. i, 
p. 141), ^^On Micrometers and Micrometry^' (vol. iv, p. 241), 
" On Microscopical Photographic Portraits" (vol. vii, p. 122). 
He also undertook to oblige his friend, the late Dr. Pereira, 
with the measurement of the starch granules of various amy- 
laceous substances for the last edition of his ^ Elements of 
Materia Medica' then in preparation, twenty-five of which 
have been published in that work. 
One of the greatest improvements in the microscope as a 
working instrument was that carried out by Mr. Jackson in 
the construction of the continuous bar, supporting the body 
of the instrument above the stage, and carrying a small 
secondary body below, the whole bar being planed from end 
to end on one level, and with rack ; this secondary body 
carrying the achromatic or other condenser, polarising prism, 
dark well, &c. In this way the axis of the instrument is per- 
fectly continuous, and no centering or adjustment is required. 
Three sets of castings were made from the patterns which 
he had constructed, two of which were given to his friends, 
Mr. Alfred White and the late Mr. Greening; and the 
patterns were then transferred to Messrs. Smith and Beck, 
and exist in the present form of their No. 1 instrument. 
In 1858 Mr. Jackson was elected one of the managers of 
the London Institution. 
In his own profession in mechanical surgery he exhibited 
considerable tact and skill ; and although such requirements 
were seldom brought into action, yet it was a source of 
great delight to him if he could by some simple contrivance 
alleviate the sufferings of his patients, and thus facilitate 
their cure. One of the last undertakings of his life was the 
production of a very simple and most efficient contrivance for 
reducing dislocations of the shoulder-joint — an operation at 
times, in very muscular subjects, very difficult to perform. 
His quiet and unassuming manners, his clear and upright 
mind, rendered him generally beloved ; and the readiness 
