Januaey 13, 1899.] 



SCIENCE. 



65 



the methods for designing and constructing 

 sewers for each are presented in full detail. 

 The combined system carries both the house 

 sewage and the storm water, while the separate 

 system carries only the former, with a small ad- 

 ditional amount of water for flushing. The 

 first system may be the more advantageous 

 when the conditions require an underground sys- 

 tem of conduits to dispose of the flood water, 

 and the second may be better when the storm 

 water can be easily carried away through the 

 street gutters. In general, the separate system 

 has been found lower in cost than the combined 

 one for small towns, and hence its extensive use 

 during recent years. 



The author's treatment of methods of flush- 

 ing and cleaning sewers is full and thorough. 

 With respect to ventilation he concludes that 

 chimneys, fans and other devices have been un- 

 successful and that no method better than al- 

 lowing free egress and ingress of air through 

 manholes, street basins and house-roof pipes, 

 has yet been found. Analyses of sewer air 

 have failed to show greater impurity than that 

 in the air of a crowded city street, whether car- 

 bon dioxide or number of bacteria be taken as 

 the basis of comparison, and hence no objection 

 except that due to sentiment can be made to 

 this method of ventilation. The methods of 

 cleaning street basins and sewers and of remov- 

 ing obstructions are explained at length ; for 

 the small pipe sewers wooden balls called 

 ' pills ' are run through with the current, each 

 successive one being greater in size than the 

 preceding ; for those larger than one foot in 

 diameter a cylindrical carriage traveling on 

 wheels is employed. The annual cost of clean- 

 ing such pipe sewers is said to range from $4 to 

 $15 per mile. 



The book is carefully written, well illustrated, 

 and contains many tables for facilitating com- 

 putations. It is the only American work which 

 deals in detail with the construction of the 

 sewers of both the combined and separate sys- 

 tems. This is the correct plan of treatment, for 

 there is no inherent reason why one is prefer- 

 able to the other, and the engineer, in each 

 particular case, must determine from the local 

 conditions the most economic and efficient sys- 

 tem. M. M. 



Cuba and Porto Rico, with the other Islands of the 

 West Indies : Their Topography, Climate, Flora, 

 Products, Industries, Cities, People, Political 

 Conditions, etc. By Robert T. Hill, of the 

 United States Geological Survey. New York, 

 The Century Company. 1898. 8vo. Pp. 

 xxviii + 429. 2 maps. 79 plates. 

 Although popular in treatment, this book 

 contains much information of value to specialists 

 in geology and anthropology. Based primarily 

 on personal observation during several ex- 

 tended journeys through the West Indies, it is 

 enriched by large acquaintance with the litera- 

 ture of the West Indies covering the centuries 

 since the discovery of the New W^orld and the 

 planting of the first European colony on the 

 Island of Martinique. In his first chapter 

 (' The Geographic Relations of the West In- 

 dies ') the author emphasizes his own general- 

 ization as to the genetic independence of the 

 three great regions of the western hemisphere, 

 North America, Central America with its An- 

 tillean extension, and South America ; in the 

 next three chapters (' The West Indian Waters,' 

 'The Classification of the West Indian Islands,' 

 and 'The Great Antilles') the subject is ex- 

 panded and illustrated by details ; while the 

 thirty-sixth chapter ('Geological Features of 

 the West Indies') is the most convenient sum- 

 mary extant of the geologic history, struc- 

 ture and mineral resources of this half-sub- 

 merged portion of the mid-American continent. 

 Additional facts concerning the geology of the 

 islands are scattered through many of the chap- 

 ters, with significant details concerning the 

 flora, fauna and climate. In the eleventh 

 chapter (' The People of Cuba'), the eighteenth 

 chapter ('The People of Porto Rico'), the 

 twenty-second chapter (' Cities and People of 

 Jamaica') the description of the Republic of 

 Haiti, and the thirty-seventh chapter (' Race 

 Problems in the West Indies'), as well as in 

 other portions of the book, the population is 

 described in a notably appreciative way, the 

 mythology and industries I'eceiving especial 

 attention. Throughout, the volume gives 

 evidence of careful observation and mature 

 thought, as well as a strong grasp of the scien- 

 tific and social problems of the region ; it gives 

 promise of becoming not merely the most 



