Mr. Spencer's philosophical series is published by D. Appleton & Co., New York, in quarterly parts (80 to 100 pages each), by subscription, at two dollars a year. "_First Principles_" is issued in one volume, and four parts of Biology have appeared. We subjoin some notices of his philosophy from American and English reviews. _From the National Quarterly Review_ (American.) Comte thus founded social science, and opened a path for future discoverers; but he did not perceive, any more than previous inquirers, the fundamental law of human evolution. It was reserved for Herbert Spencer to discover this all-comprehensive law which is found to explain alike all the phenomena of man's history and all those of external nature. This sublime discovery, that the universe is in a continuous process of evolution from the homogeneous to the heterogeneous, with which only Newton's law of gravitation is at all worthy to be compared, underlies not only physics, but also history. It reveals the law to which social changes conform. _From the Christian Examiner._ Reverent and bold--reverent for truth, though not for the forms of truth, and not for much that we hold true--bold in the destruction of error, though without that joy in destruction which often claims the name of boldness;--these works are interesting in themselves and in their relation to the current thought of the time. They seem at first sight to form the turning point in the positive philosophy, but closer examination shows us that it is only a new and marked stage in a regular growth. It is the positive philosophy reaching the higher relations of our being, and establishing what before it ignored because it had not reached, and by ignoring seemed to deny. This system formerly excluded theology and psychology. In the works of Herbert Spencer we have the rudiments of a positive theology and an immense step toward the perfection of the science of psychology.... Such is a brief and meagre sketch of a discussion which we would commend to be followed in detail by every mind interested in theological studies. Herbert Spencer comes in good faith from what has been so long a hostile camp, bringing a flag of truce and presenting terms of agreement meant to be honourable to both parties: let us give him a candid hearing.... In conclusion, we would remark that the work of Herbert Spencer referred to (First Principles) is not mainly theological, but will present the latest and broadest generalizations of science, and we would commend to our readers this author, too little known among us, as at once one of the clearest of teachers and one of the wisest and most honourable of opponents. _From the New Englander._