Communication is an essential process in the development of science. Without communication of results, it is impossible for science to advance, for positions to be challenged, etc. The "scientific paper" has been the traditional means of communication, but to say this leaves out the content. In fact, each scientific specialty is unique in the development of its own system of communication. Mathematicians may communicate using numbers and symbols; anatomists may communicate by using drawings (rather than photographs) of organs and their parts. Recently, communications have changed in molecular biology. With the advent of genome sequencing projects, a whole electronic network has been established to communicate long strings (sequences) of letters constituting the letters of DNA sequences. The current network allows only letter after letter to be listed. With the development of faster computers, etc., these communications should be sent out in a two dimensional format where the position of sequences of DNA can be shown in relationship to each other. One of the most important issues of the social study of science and technology is how these communications conventions develop. How is it that molecular biologists agree that a particular sequence of letters is meaningful? How is it that physicists accept electrical displays in a cloud chamber as communication proving the existence, say, of a quark? It is this process that Dr. Van Helden is examining. He is looking at a critical time in the development of a new language of communication in one of the most ancient of sciences: astronomy. Before the advent of the telescope, astronomy was a science communicated by words, mathematical symbols, and diagrams, but not by naturalistic representations of the heavenly body. The telescope, however, revealed celestial phenomena that were often impossible fully to describe in words, and therefore astronomers had to learn to communicate information by means of pictures drawn by the observer and reproduced as accurately as possible. Dr. Van Helden is studying the process by which these pictures were first developed and how this visual language gradually came to be accepted. He hopes to show how a fully articulated visual language, including the many essential conventions, was developed and became standard in the astronomical community. In order to complete this project, Dr. Van Helden is examining original manuscripts with their illustrations contained in libraries in London, Leiden, Paris, and Florence.