None of the Nesbitt die varieties have given the writer so many anxious hours and have required such prolonged study as the three cents of 1864. Indeed, the final solution of the problem of classification of the various dies was only arrived at after more than two years continuous research. Like the famous balancing of the egg of Columbus, the problem, when solved, is extremely simple. Looking backward on the long series of failures, it seems strange that the chief characteristics have so long escaped the attention of cataloguers. The fact, however, is patent. Even as thorough and painstaking a student as the late Gilbert Harrison who, in 1895, chronicled, as he thought, all of the existing die varieties of the three cents has failed to observe the most important differences. Indeed, in the entire philatelic literature dealing with the Nesbitt dies of 1864 there is but one allusion to the feature which constitutes the surest means for the identification of the die varieties, and this is only a single sentence contained in the Historical Notes of Messrs. Tiffany, Bogert and Rechert. It reads:-- "It is worth mentioning, however, that while dies 9, 15 and 26 (the latter the die under consideration) all have the small bust of Washington, there are small differences in each which show them to be different engravings. * * In die 26 the front hair shows only five locks and the back hair only four lines." We shall presently see that, like the three cents, red of 1853, (Die A) the diemakers have produced different groups of heads which, once known, are not only an absolute means of differentiating the varieties, but also protect the collector from acquiring a multitude of the same die. Although, as stated above, the die of the three cents rose equals that of the three cents red in the use of various heads, it is, otherwise, quite dissimilar to the first issue, as will be seen presently. As in the varieties of the two cent dies the horizontal and vertical dimensions of the three cents vary greatly. After careful research and taking the advice of experienced philatelists, it was decided to adopt only two sizes for classification: i.e. Size A:--to include all stamps measuring horizontally 24 mm. but not exceeding 25 mm. Size B:--to include all stamps measuring horizontally 25-1/2 mm. or more. In our study of the three cents red of 1853 we noted, in addition to the various heads, some minor differences in the spacing of the letters forming the inscription. Referring now to the three cents of 1864, even the unskilled eye of the layman will be struck with the surprising changes, not only in the spacing of the letters forming a word, but, also, in the relative position of the words to each other and their distance from a definite point, such, for instance, as the figure "3." The subsequent cuts well illustrate this point. [Illustration]