John W. Bennett atates that he has discovered a very effeetuecreans of preserving writings, charts, l'mkt, nd pictures, as well from injury by tijmmjtom forgery or alteration. The praeeiIPFii most simple one, and well worth knowing. It consists merely of running a very delicate coating of gutta percha over the surface of the article. It is perfectly transparent, and is said to improve the appearance of pictures. By coating both sides of an important document, it can be kept in the best preservation. It renders it waterproof, and the plan would thus be a most invaluable one for ship charte. If used on bank bills it would be a most efficient means of preventing fraud, inasmuch as no alteration could be made on the face of the bill without removing the coating, which it would be impossible to do without destroying the whole. Mr. Bennett, the discoverer of this new useful property pf gutta percha, was the late keeper of the Minot's Rock light-house, and the manufacturer of the two sledge boats, formed of willow and covered with rubber, to serve as life boats, which have received the high appreciation of Dr. Kane, of the Arctic expedition— [Exc. [It would have been well to have told the public how the thin coat of gutta percha was applied, and all about the above process for protecting bank notes, &c. In this ease we see nothing more than that gutta percha answers the purpose ol any other elastic varnish.