208 OLIVER — COLOR-SIGNALS IN MARINE SERVICE. [April 9, 



anchor, — ^just so long will it remain necessary continually to 

 improve the color material employed during actual service, and to 

 render the apparatus which is to be used the most simple in con- 

 struction that can be employed. 



The well-filled harbor, with its changeable and constantly cross- 

 ing paths containing traffic of every conceivable kind, the insta- 

 bility of the water mass itself, and the uncertain factors, such as 

 fogs, mists and snow, all show to what great degree of danger 

 every moving object placed within such a situation is exposed. 

 These conditions are far different in degree of uncertainty from 

 those that are seen in railway travel, in which the directions 

 of movement are comparatively fixed, every change of direction 

 well protected, and all of the trains carefully guarded by block 

 systems. 



The first question which arises is. Can the system of signalling 

 now in vogue in marine and naval service be so changed as to give 

 better results with less liability to error ?^ 



Experiment and trial have shown that the visual apparatus which 

 projects man's ordinary sensory powers possibly to the greatest 

 distance into space must be the sensory organ which is preferably 

 to be employed during the common routine of duty. Fixed 

 or intentionally changed color differentiations being less unstable, 

 and hence more certain for visual perception than mere recognition 

 of form and objective motion, must be that which should be 

 practically employed. As the result of experience, the coarse 

 colors, red, green, yellow, white and blue, are the ones which have 

 been found to be the best for use during maritime signalling. 

 These colors which are either placed in related situations upon 

 movable bodies (both while in motion and while at rest upon 

 bodies of water), or which are situated in fixed positions, are made 

 interchangeable and time-regulated. These colors, possessing 

 definite color-arrangement and color-sequence, are intended either 

 to express direction, signify protection or designate code-signalling • 

 varieties of work — the correct and, at times, vital answers to which 

 are dependent solely upon color recognition at distances which are 



1 Better, less complicated, and hence cheaper and more easily applied adapt- 

 ations of the Hertzian Ray apparatus might accomplish the purpose in one 

 way; but unfortunately, unless such instrumentation is automatic in action, and 

 unless its mar.agement and use can be kept constantly correct, this method must 

 be considered in the light of the futuie. 



