August 28, 1885.] 



SCIENCE, 



165 



us to form a correct judgment in regard to the 

 mortal! t3\ 



Mr. Stanley was unfortunate in the selec- 

 tion of several of the stations, particularly 

 those at Vivi and Stanley Pool. They were 

 located on high ground, and supposed to be 

 peculiarly healthy ; but at these stations the 

 hills on the two sides of the river converge, and 

 the cool breezes from the river and the valley 

 blow over the stations as through the mouth 

 of a funnel : and sickness and death are much 

 more frequent than in low stations in the val- 

 ley of the river protected from the wind by 

 the hills or trees. 



Mr. Stanley asserts, and we think he is 

 correct, that when the sanitary conditions are 

 better understood, and the exposures incident 

 to the settlement of a new country overcome, 

 proper food obtained, with temperance in eat- 

 ing and drinking, a man can accomplish as 

 much work in equatorial Africa as in temper- 

 ate Europe ; provided, as stated on another 

 page of Science^ he returns home everj^ eigh- 

 teen months for a vacation of three or four 

 months. 



The death-rate is alwa3'S high in new coun- 

 tries. In New England, and in the temperate 

 regions of America, as well as in torrid zones, 

 new settlements are always unhealthy, and great 

 mortality- prevails ; and not until permanent 

 settlements are made can we pronounce upon 

 the healthiness of any climate. We believe 

 that equatorial Africa, being nearly two thou- 

 sand feet above the level of the sea, will be 

 less unhealthy than India, or many other coun- 

 tries where white men live, and carr}^ on a 

 large and successful trade. 



The association has alread}^ planted twenty- 

 two stations up and down the valley of the 

 Kongo, and expect to plant and maintain 

 other stations ever}' fifty or one hundred miles 

 on these waters. The natives within the in- 

 fluence of these settlements are beginning to 

 labor, and bring in their productions to the 

 settlements. A small amount from each sta- 

 tion will make a large foreign export, sufficient 

 to support a railroad from Stanley Pool to the 

 ocean. 



The stations are now read}', but the mer- 

 chants cannot successfull}' establish stores for 

 trading with the natives until the railroad is 

 built. The cost of the railroad is estimated 

 by Mr. Stanley at $5,000,000 in the body of 

 his book, and at $7,500,000 in the appendix. 



All that equatorial Africa now requires, is 

 the construction of the railroad from Stanley 

 Pool to Vivi ; and we trust and believe that 

 the same good judgment, executive al)ilit3'. 



and energy, which have won success for Mr. 

 Stanley's other undertakings, will enable him 

 to raise the funds for this enterprise, open the 

 heart of Africa, and accomplish the objects of 

 the association. Gardiner G. Hlbuakd. 



COMPOSITE PORTRAITURE. 



The process of composite photography has 

 been applied to the solution of two problems : 



1. Given a series of objects having in common 

 an interesting characteristic, to find a single 

 type which shall represent the whole grou[j. 



2. Given a series of representations of the 

 same object, to find a single representation 

 which shall give a superior effect b}- com- 

 bining the strong points, and neglecting the 

 defects, of each of the series. The latter 

 problem is by far the simpler. The composite 

 of six medallion heads of Alexander the Great 

 ma}' be taken to represent the real Alexander 

 better than any one of the originals, because the 

 probability of the six artists having Introduced 

 the same inaccuracy is very small. In the 

 first problem, however, we are introducing an 

 essentially new face, — a type representing par 

 excellence the peculiar characteristic for which 

 the originals were grouped together. In com- 

 bining the portraits of criminals, the object is 

 to get a type of criminality ; in combining the 

 portraits of national academicians, one of rec- 

 ognized scientific ability. 



Other methods of producing a type are when 

 the artist puts on paper the general eftect of 

 more or less unconscious observation of physical 

 peculiarities in the class of persons represented ; 

 or when the anthropologist selects among a 

 number of savages, for instance, one who was 

 judged to have all the distinctive marks of his 

 tribe in neither an exaggerated nor a deficient 

 degree, and yet combined with them no indi- 

 vidual eccentricities, — in short, that much- 

 talked-of average man, whom one does not 

 meet every day. Composite photography aims 

 to take this process out of the hands of erring- 

 judgment and vague imagination, and reduce 

 the art of type-getting to a mechanical one of 

 combining photographs. 



In several cases, when various images have 

 been combined to elicit a type, it has happened 

 that the resultant has been remarkably similar 

 to one individual of the group represented. 

 This was strikingly illustrated in the portraits 

 published in Science, No. 118. Mr. Galton men- 

 tions, that in one such case he took a second 

 composite, omitting the face which resembled 

 the first composite, and the two pictures thus 



