(a) to assisting persons to obtain education other than primary when the expenses thereof would without such assistance be beyond their means. in particular and without limiting the generality of the foregoing or the discretion of the governors, such income may be applied to assist persons to obtain education to fit them for any profession or calling or for a career in any department of natural or applied science by means of attendance at university or college courses either as external or internal students or by means of professional articles or articles of apprenticeship; or (b) to or towards the maintenance or assistance of any school college institution or centre which is a charity and provides educational or research facilities or vocational training for scholars or students; or (c) to assisting teachers to visit places outside the united kingdom for the purpose of improving their professional and technical qualifications by the study of conditions and methods of education overseas.