The President's Address. 
67 
The contributions to the vast and inviting field of Natural 
History have unfortunately been restricted to one of the 
lowest types of organization, — the Diatom acese. In this de- 
partment we are indebted to the habitual industry and skill 
in delineation of Dr. Greville for four papers : 
I. A Monograph of the Genus Auliscus/^ 
II — IV. " Descriptions of new and rare Diatoms/^ Series 
IX, X, XI. 
Mr. H. S. Lauder has given a descriptive paper of several 
forms of new diatoms, and we are indebted to our indefatigable 
Secretary, Mr. Roper, for a paper *^^0n the Genus Licmophora.^^ 
In the interest of science I cannot here avoid expressing a 
regret that some attention has not been devoted, by those 
who have the opportunity of so doing, to the more difficult, 
but far more important, investigation of the development and 
specific diff'erences of these minute but interesting organisms. 
On the subject of the improvement of the microscope and 
its accessories, we are indebted for two communications from 
Mr. R. Beck : 
I. A Description of a new Stand for a Single Microscope, 
with a Biuocular Arrangement.''^ 
II. On the new forms of Reversible Compressors.^^ 
In the contrivances here described the author has exercised 
his accustomed ingenuity in placing at our disposal useful 
and convenient appliances. 
I am happy to have the opportunity of stating that during 
the past year we have not sustained, either by decease or 
resignation, the loss of any member, whose name has been 
made familiar to us by any important services in promoting 
the objects of the Society. 
Our present numerical strength is 353, compared with 337 
at the period of the last anniversary, showing an increase of 
sixteen members. 
Our library has been augmented by many volumes. The 
collection of mounted objects has been enriched by several 
liberal donations, amongst which may be mentioned thirty- 
four specimens of vegetable fibre presented by Mr. Crum, 
and thirty of diatoms from Prof. Jones, of Calcutta. It has 
also been augmented by the purchase of thirty-seven slides. 
The number of objects, which, in 1858, amounted to only 350, 
had at the last anniversary advanced to 1100, and at the 
present time is 1235. But the improvement in our instru- 
mental department is the most conspicuous, in reference to 
which it is my duty to recall to your recollection the munifi- 
cent donation of Mr. Ross of a complete microscope of his 
newest and best construction^ with a series of objectives 
