36 The Pres'ideut's Address. 



eflBcient instniraent for usinz the doublet lenses introuuccd 

 by the late Dr. WoUaston ; the two lower pairs of these he 

 framed and figured for himself. This was followed by the pro- 

 duction of a large-sized instrument, capable of effecting all 

 that the best microscopes of that period were able to do. At 

 the tuming-lathe and planing-machine he was a thorough 

 workman, and these instruments he had constructed on his 

 own plans, and much of them by his own hands. He was the 

 ■first to show the great importance of employing the latter for 

 perfecting the instrument and economising labour. 



Mr. Jackson was one of the original members of our Society 

 at its formation in 1840, and most of his various suggestions 

 for the improvement of his favorite instrument have been 

 laid before the members. 



The first of these was a paper '•' On Microscopic Measure- 

 ment,'' read September 23d, 1840, and printed in the 'Micro- 

 scopic Journal,^ vol. i, p. 11 — a subject with which his name 

 has become so intimately connected. 



In April, 1841, he described a portable candle-lamp for 

 illumination by reflection, some observations on which will 

 be found in the ' Microscopic Journal,^ vol, ii, p. 77. This 

 was followed in November, 1847, by his paper on "The Eye- 

 piece Micrometer,^' published in the ' Transactions of the 

 Society,' vol. ii, p. 134. 



The small but elegant little ruling-machine, which he con- 

 structed for the division of these micrometers, is a most eflB- 

 cient arrangement, and although, I believe, never figured or 

 described, vet he had no hesitation in exhibiting it to anv 

 person who was interested in such matters. 



It was about this period that he also constructed a very 

 complete and serviceable cutting-machine for producing thin 

 sections of woods, &:c. 



In 1852 !Mr. Jackson was elected President of this Society, 

 and I am sure that the members will all bear witness with 

 me in stating that he was at all times most active in advanc- 

 ing the true interests of the Society. 



In conjunction with Dr. Carpenter, Dr. Lankester, and your 

 President, he was appointed by the Council of the Society of 

 Arts a member of the committee, to assist in awarding their 

 premium for the best and cheapest microscopes. 



In May, 1857, he exhibited and described a new form of 

 travelling microscope, four of which he has constructed as 

 presents to vainous relatives. 



Soon after the process of photography on collodion had 

 become practised, Mr. Jackson turned his attention, with his 

 accustomed clear-headed assiduity, to this engaging branch of 



