PLATE 4. 



Photography of Opaque Objects. 



A GROUP OF MARINE SHELLS FROM THE W. DONEGAL COAST x 8 



Objective Grouch 2" Achromat. Stopped down. 



Ocular None. 



Illuminant ... Sunlight reflected from a co/icave mirror and 

 focussed on to the object. 



Plate Imperial Special Rapid. 



Ex[)osn re 20 sec. 



A small diaphragm was placed between the component lenses of 

 the objective to give depth of focus. 



Diameter of aperture of diaphragm, 1.5mm. 



Photography of Plate Cultures of Micro-organisms. 



Dark ground illumination. 



Penicillinm () Ian cum, young colony of mould on gelatine platex2o 



Objective Seibert Xo. 0. 36mm. 



Ocular Seibert I. 



Condenser ... Abbe, with wheel stop. 

 Illuminant ... Sunlight reflected from the mirror. 



Plate II ford process. 



Uxposn re 5 sec. 



Pctri dish, without cover, laid on microscope stage. 



Photos W. B. R. 



H. L. H. To follow Plate 3 and page 32. 



