This study of the Spanish cosmographic juntas is directly related to two of the papers which I have read before the Society of the History of Discoveries. One was called Science by Litigation, dealing with the problems of the compass and maritime chart, and the other, entitled Science by Competition, treated the problem of ,determining longitude.! An alternative title for this paper on the Spanish cosmographic juntas might be Science by Consultation. All three studies are inquiries into the social mechanism by which the work of the cosmographers, their theories, their experiments and accomplishments, found room in a world of inherited ideas and traditional practices of navigation and relevant branches of science. The inquiry is germane to the history of the discoveries because the spectacular advance of scientific speculation and the growing opportunities for experimentation in sixteenth century Spain were by and large based on information coming from the newly discovered lands, seas and societies, and upon the challenges to tradition posed by it. This needs no demonstration. Cosmographers of any distinction had to come to terms with the expanded environment and the data from the broadened field of observation made available by the voyages of discovery and exploration. My inquiry concerns experiences with the social mechanisms available to the cosmographers of the sixteenth century to define the nature of their knowledge (technological and scientific), to get opportunities for their work and recognition for their results. The first two articles showed how the nature of the new knowledge was tried in the wrong forums, that is to say, scientific knowledge cannot be judged as to its validity or truth in a court of law, nor can competition lead to the solution of an as yet insoluble problem or one for which neither the intellectual nor the experimental apparatus has been devised. This paper sets out to describe another mechanism, that of the variously constituted juntas used by the Spanish crown to tap the reservoir of scientific intelligence for practical purposes, that is, it deals with science applied and with the feedback from this into theory and experiment. Again, the relations between the conceptual basis of science and the use of experimental results are seen to be interdependent and it becomes clearer that the social mechanism which promotes the one does not necessarily benefit the other.