6 



THE VOYAGE OF H.M.S. CHALLENGER. 



specimens may be secured from injury at a moment's notice. The racks for large bottles 

 should be carefully made, and should be rather deeper in proportion than shown in the 

 woodcut of the laboratory. The bottles should fit into two circular apertures in wood, 

 one at the bottom of the bottles, the other at about half their height. With such an 

 arrangement it is unnecessary to wedge them in position in heavy weather, and there 

 is no fear of specimens being lost owing to a sudden lurch of the ship. 



Fig. 2. — Zoological Laboratory on the Main Deck. 



A long table was fixed across the laboratory, with its end close up to the port. It was 

 found that only at either side of the table, close to the port, could a really satisfactory 

 light for the use of the microscope be obtained. It should therefore be a matter of care, 

 that in future the ports of any similar laboratory should be fitted with windows con- 

 structed with as little opaque material as possible. Those of the Challenger laboratory 

 might certainly have been improved in this respect had the matter received attention 

 when they were constructed. Plate glass windows in iron frames would probably be 

 best. In harbour or during very calm weather, the light from the skylights could be 

 used for the microscope with advantage, but whenever the ship was in motion, the 

 tables so constantly shifted their angle of inclination to the light, that it was 

 impossible to keep the field illuminated for many seconds together. At the two seats 



