MAC CULLAGH
as controversialist.

Mac Cullagh on several occasions found himself in contention with regard to priority in obtaining new results. On 30th November 1838 a letter from M. Neumann of Königsberg, was read out at an Academy meeting. This had been addressed to Hamilton, as President, and claimed priority over MacCullagh in establishing the laws of crystalline reflexion and refraction. These claims were trenchantly refuted by MacCullagh. An opposing theory of the aether formulated by the French mathematician Cauchy, whose conclusion had achieved a widespread acceptance, was rather brusquely rejected; `from these simple considerations it is evident that the theory of M. Cauchy is unsound; but a closer examination will show that it is entirely without foundation, and that it ts directly opposed to the very pheomena which it professes to explain.' MacCullagh was not lacking in self assurance when at the age of 24 he claimed to have anticipated Hamilton's discovery of conical refraction. He wrote as follows to the Philosophical Magazine `when professor Hamilton announced his discovery of Conical Refraction he did not seem to have been aware that it is an obvious and immediate consequence of the theorems published by me, three years ago...'. Whereas this may have been true the fact was that MacCullagh had not proceeded to draw the relevant conclusions from his results and his implied criticism of Hamilton was not justified. Hamilton was understandably put out and MacCullagh had to be prevailed upon by Lloyd to at least partially recant. In the following issue of the Philosophical Magazine he wrote, `The introductory part of my note which appeared in your last issue was written in haste, and I have reason to think it may not be rightly understood'.