SYMBOLIC NOMENCLATURE. 109 



in such stages of manufacture as to make their destination uncer- 

 tain, the indications of pattern are also omitted. 



For a similar reason a completed member requires no number, 

 for it expresses the union of all its components. It is like the 

 name of a family of which we call the members John Smith, Ann 

 Smith, etc., and designate them collectively as the Smiths, what- 

 ever their number. To pursue the analogy, John Smith's leg 

 would be a component of that member of the Smith family, and 

 his foot a piece of that component, etc. 



So, also, when members are united we drop the member symbol, 

 because the combination can no longer refer to any one of them. 

 Their union forms the staple in various stages of completeness, 

 the most advanced of which we designate by the descriptive 

 symbols only. Having advanced as far as possible, all further 

 progress must be negative ; consequently additions to the symbol 

 of completeness indicate increasing degrees of departure from it. 

 These additions are numbers progressively arranged. 



5. I would reverse the last recommendation of Mr. Smith relat- 

 ing to obsolete objects, by giving to the first model of any object 

 its plain number and designating any changes from that model 

 by a suffix. The other method takes the back track too often. 



For example, supposing the symbols to have been in operation 

 for the last eleven years, the receiver, model 1868, would be 

 S-F-B. II ; when shortened in 1870, it would have become 

 S-F-B. u, a; altered to cal. 45 in 1873, it would have been 

 called S-F-B. 11, b, and changed by the memorandum of July I, 

 1879, it would now be S-F-B. 1 1, c. 



Such a course would deal with each change directly when it 

 was made, would be historical, suggestive and most convenient 

 in marking drawings, tools, patterns, gauges and obsolete com- 

 ponents in store. 



