S. 3, Knife 3, 221 × 97 mm. Official. S. 7, " 13, 224 × 96 mm. " S. 8, " 14, 241 × 100 mm. Extra Official. S. 8, " 15, 249 × 104 mm. " " S. 8, " 16, 260 × 110 mm. " " S. 8, " 17. 271 × 118 mm. " " Letter sheets on blue and white paper with this die are essays or trial printings. FOUR CENTS. ONE CENT BLUE (FRANKLIN) AND THREE CENTS RED (WASHINGTON). The reason for the issue of this, the only compound stamp of the U. S. Post Office, has already been stated in the introduction to the one cent. The two stamps were impressed side by side, the one cent to the left and the three cents to the right. The Department issued two sizes of these rather scarce compounds, officially called size 2 and 3. Of the first there exists but one knife, i.e. knife 8 (137 × 77 mm), and of the second two knives, i.e. knives 2 and 9, both measuring 139 × 83 mm. All envelopes exist on white and buff paper, except perhaps variety 5. There are five different combinations of these compounds, which are as follows: ONE CENT. THREE CENTS. Variety 1. 3 × 8 Variety 2. 4 × 4 Variety 3. 6 × 8 Variety 4. 8 × 1 Variety 5. 10 × 8 It will be noted that the same variety of the three cents is used with three different combinations of the one cent. By far the rarest of the entire series is variety 5 which represents the Franklin die, in which the back and front of the bust cut into the inner frame line. The writer has seen a few copies of this variety on white paper but none on buff. From the reports of the Postmaster-General it has been ascertained that the compound stamp was issued only during fifteen months, ending June 30, 1863. On account of the short time that these envelopes remained on sale but 127,250 were issued. This explains their rarity. SIX CENTS: RED. HEAD OF WASHINGTON: SIX RAYED STARS FOR SIDE ORNAMENTS. OVAL 20 × 24 MM. This die, which was in use from October, 1860, to August 15, 1861, presents us with a new head, which was retained for the next higher denomination, the ten cents, green. Why the head used for the three cents was abandoned by the die maker we do not know. The principal new feature is a very short heavy front-lock which ends far from the ear-lobe. In addition to the front-lock there are three long clusters of hair in the front and four in the rear, of which the two lowest reach into the queue. From the middle of the side-lock extends the wedge-shaped lowest front-lock. It slants but a little distance across the ear-lobe. A long straight lock, made up of three strands, runs from the ear-lobe into the queue. The size of this envelope is "Official" or No. 7, measuring 221 × 98 mm. It is found both on white and buff paper and is very rare. TEN CENTS: GREEN. HEAD OF WASHINGTON; SIX RAYED STARS FOR SIDE ORNAMENTS. OVAL 20 × 24 MM.