In 1873 an essay of George Romanes gained the Burney Prize at Cambridge, the subject being _Christian Prayer considered in relation to the belief that the Almighty governs the world by general laws_. This was published in 1874, with an appendix on _The Physical Efficacy of Prayer_. In this essay, written when he was twenty-five years old, Romanes shows the characteristic qualities of his mind and style already developed. The sympathy with the scientific point of view is there, as might be expected perhaps in a Cambridge 'Scholar in Natural Science': the logical acumen and love of exact distinctions is there: there too the natural piety and spiritual appreciation of the nature of Christian prayer--a piety and appreciation which later intellectual habits of thought could never eradicate. The essay, as judged by the standard of prize compositions, is of remarkable ability, and strictly proceeds within the limits of the thesis. On the one side, for the purpose of the argument, the existence of a Personal God is assumed[1], and also the reality of the Christian Revelation which assures us that we have reason to expect real answers, even though conditionally and within restricted limits, to prayers for _physical_ goods[2]. On the other side, there is taken for granted the belief that general laws pervade the observable domain of physical nature. Then the question is considered--how is the physical efficacy of prayer which the Christian accepts on the authority of revelation compatible with the scientifically known fact that God governs the world by general laws? The answer is mainly found in emphasizing the limited sphere within which scientific inquiry can be conducted and scientific knowledge can obtain. Special divine acts of response to prayer, even in the physical sphere, _may_ occur--force _may_ be even originated in response to prayer--and still not produce any phenomenon such as science must take cognizance of and regard as miraculous or contrary to the known order.