Tacticians were now mainly absorbed in working out this form of attack and the methods of meeting it, and Russell's elaborate articles for handling squadrons and subdivisions independently may well have had this intention.
The new phase of tactical opinion is that which we find expounded in Pere Hoste's famous work, _L' Art des armees navales, ou Traite des evolutions navales_, published in 1697 at the instigation of the Comte de Tourville.

The author was a Jesuit, but claims that he is merely giving the result of his experience while serving with the great French admirals of that time, who had learned all they knew either as allies or enemies of the English.

'For twelve years,' he says in his apology for touching naval subjects, 'I have had the honour of serving with Monsieur le Marechal d'Estrees, Monsieur le Duc de Mortemart, and Monsieur le Marechal de Tourville in all the expeditions they made in command of naval fleets; and Monsieur le Marechal de Tourville has been kind enough to communicate to me his lights, bidding me write on a matter which I think has never before been the subject of a treatise.' The whole system of tactics that he develops is based, like Russell's, on the single line ahead and the independent action of squadrons.

The passages in which he elaborates the central battle idea of concentration by doubling are as follows: 'The fleet which is the more numerous will try to extend on the enemy in such a manner as to leave its rearmost ships astern, which will immediately turn [_se repliera_] upon the enemy to double him, and put him between two fires.

_Remark I_ .-- If the more numerous fleet has the wind it will be able more easily to turn its rear upon that of the enemy, and put him between two fires.