Mat is, 1883.1 



SCIENCE. 



425 



like and masterful views of women's powers 

 and privileges. Women, he thought, ought 

 to have everj* thing provided for them, and 

 every trouble taken off their hands : so the less 

 they meddled with business in any form, the 

 better. But these very j'oung notions gave 

 v/ay, as he saw more of life, to wiser and more 

 practical ones. He found that women were 

 not utterly helpless ; and his love of justice, 

 combined with his better opinion of their pow- 

 ers, made him quite willing to concede to them 

 as much as he would have desired for himself; 

 nameh", full scope and opportunity for the ex- 

 ercise of all their faculties. This was shown 

 by his giving lectures gratuitously' in the Ladies' 

 college for tlie first year after its foundation, 

 and b}' the interest he felt in the success of 

 those brave women who first attempted the 

 stud_y of medicine." 



De Morgan's letters are of a kind which it is 

 ver}^ interesting to receive at the natural inter- 

 vals at which the}' are written. When taken 

 en masse, the logico-mathematical language 

 in which thej' are couched, amusing in small 

 doses, and their wit, excellent but monoto- 

 nous, become wearisome. It is too much like 

 sitting down to a continuous reading of the 

 Budget of paradoxes. 



In regard to his ideas on religion, De INIor- 

 gan was always extremely reticent ; but in 

 spite of the disastrous effect of his early train- 

 ing, and in spite of his strong aversion to un- 

 founded beliefs, he preserved a deeply religious 

 tone of mind, and a firm faith in the Christian 

 religion. At the same time, nothing could be 

 more frank and uncompromising than the Vfny 

 in which he meets the renewed insistance of 

 Ms mother, upon the occasion of the death of 

 a sister to whom he was much attached, that 

 he should renounce his freedom of opinion. 

 His letter, if somewhat severe and untender, 

 is still a splendid example of that strong rec- 

 titude of mind whicli was characteristic of 

 him, and which did not permit him to gain 

 any thing, even family harmony, at the cost of 

 concealment. 



The last j'ears of De Morgan's life were 

 years of disappointment and grief. The uni- 

 versity in which he had labored with untiring- 

 en ergj' until the age of sixty became once more 

 impossible to him. The reiterated pledges of 

 its founders and subsequent directors, that the 

 essence of its being should be absolute and 

 complete religious equality in everj' portion 

 of its organization, were broken ; and De Mor- 

 gan could not lend his countenance to a less 

 liberal or a. more worldlj' line of policy. Upon 

 the refusal of the council to appoint to the 



chair of mental philosophy and logic the Rev. 

 James Martineau, who had been recommended 

 hj- the senate on account of his wide reputa- 

 tion as a preacher of an unpopular sect, De 

 Morgan once more handed in his resignation. 

 A 3'ear later occurred the death of his second 

 son, George, a young man of great mathe- 

 matical promise, and oue of the two first pro- 

 jectors of the present Mathematical society. 

 From this time De Morgan's health and vigor 

 were not what thej' had been ; and after an 

 attack of congestion of the brain, from which 

 his recover}- was slow, he died in 1871 of ner- 

 \'ous prostration. 



WHITE'S FOSSIL MOLLUSKS OF NORTH 

 AMERICA. 



A review of the non-marine fossil Mollusca of North 

 America. By C. A White. Washington, Gov- 

 ernment printing-office, 1883. 1, 144, 3 p., 32 pi. 

 sm. f°. [Annual report U. S. geological sm-vey, 

 1881-82, separately paged.'\ 



No work is more useful to the biologist, 

 whether his studies relate to recent or to fossil 

 forms, than the collection and careful illustra- 

 tion of scattered material. In the book under 

 consideration, Dr. White has produced for the 

 student of moUusks, in either their recent or' 

 their paleontological relations, a much-needed 

 and permanently valuable work of reference. 

 Owing to their wide range, fecunditj'' and ac- 

 cessibility, the class of moUusks included under 

 his title are, all over the world, better known, 

 more thbroughlj' studied, and more easily col- 

 lected, than those of the sea. Hence it is to 

 be expected that the material for learning what 

 lessons thej^ have to teach will be available for 

 students much sooner with the land and fresh- 

 water moUusks than with the marine species 

 considered as a class. Publications such as 

 this, perhaps more than any other single means, 

 will serve to shorten the time which must elapse 

 before such a condition of the science is reached. 

 Stratigraphical paleontologj' will not be so much 

 the gainer as biology' in a wider sense, since 

 the uniformitjf of lacustrine and fluviatile con- 

 ditions interferes with that differentiation which 

 makes of some groups of marine moUusks valu- 

 able inclices of geological time. 



Dr. White has brought together excellent 

 figures of nearly all the species of the groups 

 under consideration belonging to North Ameri- 

 can paleontologj', from the oldest strata in 

 wliich they are known, to and including the 

 miocene tertiary'. One doubtfullj' pliocene spe- 

 cies is mentioned ; but the fossils of the later 

 marls, and such deposits as that of the Colorado 



