CHRONOLOGICAL SIGILS.

The article provides information on Charles Bishop's recently proposed use of "coden" in documentation to identify uniquely and briefly each paper published in scientific periodicals. This coden would consist of a four-letter abbreviation to identify the journal, followed by the volume number, followed by the number of the page on which the paper commences. Some journals that publish more than one volume a year start numbering the volumes afresh at the beginning of each year. If two or more papers commence on the same page. they must be distinguished. The coden proposed by Bishop does not specify the date. The main question for debate is whether knowledge of the year is worth the price of one extra digit.