In New York the cross streets as they run east or west of Fifth Avenue are named east or west. In crossing each avenue eastward or westward the numbers jump to the next whole hundred, as in Philadelphia. The building at the southwestern corner of Third Avenue and East 23rd Street is 162; that on the eastward corner, opposite, is 200. Thus in cross streets the number of a house tells us between which avenues it will be found. In hotels and office-buildings, throughout America, the numbering greatly aids an inquirer. Room 512, for example, will be found on the fifth floor; immediately beneath is 412 on the fourth floor; directly above is 612 on the sixth floor, the first figure always denoting the floor. Classifying Books. A capital use of numerals to convey information is that devised by Melvil Dewey, formerly State Librarian of New York at Albany. He divides literature into ten great departments, giving each of them one of the ten numerals. History, in this scheme, is represented by 9 as the first figure in the number of a book; the second figure refers to the geographical division to which the work belongs, thus 7 means North America; the third figure standing for the political division treated by the book, 1 representing the British Empire. A work on Canadian history, therefore, will bear as its number, 971. An Advance in Scientific Signaling. Everybody knows what a money-saver is the familiar code of the ocean cables, by which “befogged” stands for “Will the property be advertised for sale?” reducing the toll by the cost of six words. Most of the terms in a code are not dictionary words, but such collocations of letters as “carthurien” and “brankstrop.” A new code devised by Mr. Charles G. Burke, of New York, proceeds upon the use of four numerals, 1, 2, 3, 4, which he transmits in the fewest signals possible to a cable, 1 is a dot; 2 a dash, 3 a dash-dot; 4 a dot-dash. This is how they look when received on paper in comparison with ordinary messages:-- [Illustration: Present code. Automatic transmitting strip.] [Illustration: Signals received from above strip.] [Illustration: Burke code. Transmitting strip.] [Illustration: Signals received from above strip.] [Illustration: The Burke numerals forming the permutations.] [Illustration: A Burke combination of 8.]