26 



PROCEEDINGS OF THE NATIONAL MUSEUM 



40-49 Fog at the time of observation. 



40 Fog at a distance at the time 



of observation, but not at 

 the ship during the last 

 hour, the fog extending to a 

 level above that of the 

 observer. 



41 Fog in patches. 



42 Fog, sky discernible. 



43 Fog, sky not discernible. 



44 Fog, sky discernible. 



45 Fog, sky not discernible. 



46 Fog, sky discernible. 



47 Fog, sky not discernible. 



Has become thinner during 

 preceding hour. 



No appreciable change dur- 

 ing preceding hour. 



Has begun or has become 

 thicker during preceding 

 hour. 



48 Fog, depositing rime, sky 



discernible. 



49 Fog, depositing rime, sky 



not discernible. 

 50-99 Precipitation at the ship at the time of observation. 

 50-59 Drizzle at time of observation. 



50 Drizzle, not freezing, 



intermittent. 



51 Drizzle, not freezing, 



continuous. 



52 Drizzle, not freezing, 



intermittent. 



53 Drizzle, not freezing, 



continuous. 



54 Drizzle, not freezing, 



intermittent. 



55 Drizzle, not freezing, 



continuous. 



56 Drizzle, freezing, slight. 



57 Drizzle, freezing, moderate 



or thick. 



58 Drizzle and rain, slight. 



59 Drizzle and rain, moderate 



or heavy. 



Slight at time of 

 observation. 



Moderate at time of 

 observation. 



Thick at time of 

 observation. 



