The TEN CENTS is light and dark green. The lighter shade is generally called a yellow-green, but the two shades differ only in intensity. The TWELVE AND FIFTEEN CENTS also vary from grey to deep black. The TWENTY-FOUR CENTS is violet, and pale or dark lilac. The THIRTY CENTS is of two shades of orange, and an orange-brown. The NINETY CENTS is faint deep blue and indigo blue. The number of the several values of these stamps issued, without the _grille_ is approximated as follows: it being not quite certain whether a few with the grille were not issued prior to the dates to which the enumeration is made. 1 cent 91,256,650 2 cents 254,265,050 3 cents 1,847,559,100 5 cents 8,258,460 10 cents 28,872,780 12 cents 7,639,525 15 cents 2,139,300 24 cents 10,238,650 30 cents 3,208,980 90 cents 337,770 XXI. THE ISSUE OF 1867-9. The Act of the XXXIX Congress, Session I, Chapter 114, Section 7, approved June 12th, 1866, entitled an Act to amend the Postal Laws, had provided among other things. "Sec. 7. And be it further enacted: that whenever it shall become expedient in the opinion of the Postmaster General to substitute a different kind of postage stamps for those now in use, he shall be, and is hereby authorized to modify the existing contracts for the manufacture of postage stamps, so as to allow the contractors a sum sufficient to cover the increased expenses, if any, of manufacturing stamps so substituted." The Report for the Postmaster General for the year ending June 30th, 1867, states that experiments had been made in printing postage stamps on an embossed paper, which appeared to offer a fair guarantee against fraud; that the tissues of the paper were broken by the process, so that the ink of the cancelling stamps penetrated the stamps in such a manner as to render cleaning impossible; that the adhesiveness of the stamps was also increased, to say nothing of other advantages, which recommend the invention. Some of these curious experiments will be noticed in the chapter on Essays. The plan adopted was, however, to emboss the stamp, after it was printed, with a series of small square points, arranged in the form of a rectangle, much in the same way that checks are sometimes treated to prevent alteration. This breaks the tissues of the paper. The French collectors call this a _grille_, or grating, which it resembles. There were several varieties used on this issue, and they were applied to the stamps then current, without other change in the design, paper, color or gum. ISSUE OF 1867 TO 1869. The first variety was a grille covering the entire stamp, adopted May 8th, 1867, and applied only to the; 3 cents, rose, perforated 12, grilled all over.