METHODS OF USING THE 



Microscope, Camera-Licida and Solar Projector 



FOR PURPOSES OF EXAMINATION AND THE 

 PRODUCTION OF ILLUSTRATIONS. 



By N. a. COBB 



Being the Fikst Annual Eepoet oi" the Division of Pathology and Physiology, 

 Experiment Station of the Hawaiian Sugar Planters' Association. 



To the Experiment Station Committee, 



Hawaiian Sugar Planters^ Association : 



It is using a misnomer to call this an Annual Report, inas- 

 much as the Division of Pathology and Physiology has been in 

 existence as a partially organized force for only about three 

 months. Under the circumstances the energies of the Division 

 have of course been devoted mainly to securing the proper 

 facilities for its work in the form of laboratory equipment and 

 land. I think I can not do better under the peculiar cuxum- 

 stances of the case than to describe at some little length the 

 more original of the features embodied in the Laboratory. 



The nature of this building has been mentioned in the Annual 

 Report of the Chairman of the Committee on Experiment Sta- 

 tions, and the illustrations inserted there and elsewhere in this 

 report give a good idea of its general appearance, both ex- 

 ternally and internally. The features to which 'I will call partic- 

 ular attention are those found in the Microscope Room, Illus- 

 tration Room, and Dark Room. 



THE MICROSCOPE ROOM. 



For many years it has been customary in the best laboratories 

 to mount various instruments of precision upon pillars of stone 

 or masonry deeply imbedded in wells in the ground and passing 

 upward throuigh the floors of the laboratory without contact. 

 The object of this arrangement is to prevent tremors, which are 

 of constant and inevitable occurrence in an inhabited building, 

 from being transmitted to the instrument; the earth receives 

 these tremors, and, within the limits of the precision of the in- 

 strument, they are nullified. Galvanometers, seismographs, 

 balances and other instruments are mounted in this man- 

 ner. It is not often that the microscope has received such 

 special attention, but wherever hig'h powers are used and espe- 

 cially when photo-micrographs are being prepared, or whenever 

 high power camera lucida drawings are being made, the reduc- 

 tion of vibration is an important factor in the success of the 



