1016 Transactions of the American Institute. 



working out the details of this nomenclature, it would doubtless 

 be found that many additions and corrections would be necessary. 

 * * * In a nomenclature for organic compounds something 

 more is required than the name of elements and the expression of 

 their number by vowels.' This author gave new names to all the 

 elements, yet failed to express any but the simplest facts of com- 

 bination. After devising a very defective numerical system, in 

 which the value of vowels depended on their position, he was com- 

 pelled to coin new words for each nucleus, having no reference to 

 their composition, thus virtually abandoning the vowel plan. 



" By scrutinizing Gmelin's method, any one who comprehends the 

 requirements of a complete nomenclature, will be convinced that 

 the scheme cannot be used as a substitute for the notation. Simi- 

 lar objections may be made to Mansfield's method (see Theory of 

 8alts, London, 1865). This author shows that the use of the five 

 vowels as numerals was of English origin, and was employed, 

 although not in connection with chemistry, in Dr. K. Gray's MemO' 

 via Technica (new edition, Oxford, 1831). 



" I claim for my scheme,— which is adapted to Gerhardt's unitary 

 system, and may properly be called " the unitary nomenclature " — 

 as its chief merit, simplicity of construction. Accepting the old 

 names of the elements, I have so modified them that each begins 

 with its old symbol and ends with its new; the latter so generally 

 corresponds with the former that only seven new characters are 

 introduced. With these materials, and a more perfect numerical 

 method than that employed by Gmelin, I have succeeded in repre- 

 senting, by a combination of letters and syllables, bodies of the 

 most intricate structure. For the first time systematic terms have 

 been applied to radicals, so-called residues, and their numerous 

 combinations. Every hydrocarbon has an appropriate symbolic 

 appellation, and not only polymers but isomers have distinctive 

 names. The only paper which I have yet published on the subject 

 contains word-formulae for more than seven thousand compounds. 



" Although the unitary nomenclature is commensurate with all 

 possible atomic combmations, I do not claim that the new names 

 would be preferable to a portion of the corresponding names now 

 employed, nor do I entertain the hope that any part of the new 

 scheme will l)e adopted until combinations of terms on the old 

 plan become too cumbersome for common use. 



"I am, &c., "SAMUEL D. TILLMAN. 



"American Institute, New York, Mai/ 11, 1867." 



