The original drawings of the plates of _The Birds of America_ were sold by Mrs. Audubon on June 2, 1863, to the Historical Society of New York,[246] and a few of them are now displayed in its building in that city; it is still hoped that a fire-proof and adequately lighted hall can be constructed so that the whole of this great series of pictures may be exhibited under more perfect conditions. The artistic beauty and historical value of these drawings, with the added charm which personal association has so richly supplied, would render Audubon's "Book of Nature" one of the most unique and interesting exhibits in the New World. The collection appears to be nearly complete, although some notable pieces, such as the Wild Turkeys, are lacking, but there are other drawings, and some of early date, which were never reproduced; all are inclosed in the original portfolios, scarred by hard knocks and the tooth of time, massive, leather-bound containers, which two strong arms would raise with difficulty from the ground. Most of these originals are mounted on a gray backing, with plate margins in each case indicated by ink lines. As was noticed in an earlier chapter, many original legends and notes written by Audubon's pencil or pen still remain on the drawings, though many have been trimmed off or erased; these include names of localities and dates, and directions to the engraver for changes in the background and composition or for any improvement of the whole or a part. As a further illustration of the care which Audubon exercised over the minute details of his great undertaking, we will reproduce the penciled orders on the drawing of the Great White Heron (Plate cclxxxi), which shows an adult male performing the gymnastic feat of seizing a large striped fish, a view of Key West forming the background: "Keep closely to the sky in depth & colouring! have the water a _Pea-green_ tint. Keep the division of the scales on the leg in fact white in your engraving—The colouring over these will subdue them enough! finish the houses better from the original which you have; have the upper back portion very mellowing in the outline." Again, on the drawing of the Great Cinereous Owl (Plate cccli), we read: "Raise the bird about 4 inches on the copper—higher than in the Drawing, and put in a landscape below of Wild Mountains," a direction which in this instance was not followed, for the bird was eventually shown on a branch against the sky.