COMPOSITE PORTRAITS. 469 



ness of the family in question. The other cousins I should disregard. 

 The weights, as previously mentioned, would be bestowed by giving 

 proportionate periods of exposure. 1 



Composites on this principle would undoubtedly aid the breeders 

 of animals to judge of the results of any proposed union better than 

 they are able to do at present, and in forecasting the results of mar- 

 riages between men and women they would be of singular interest 

 and instruction. Much might be learned merely by the frequent use 

 of the double-image prism, as described above, which enables us to 

 combine the features of living individuals when sitting side by side 

 into a sino-le imao-e. 



I have as yet had few opportunities of developing the uses of the 

 composite photographic process, it being difficult without much expla- 

 nation to obtain the requisite components. Indeed, the main motive 

 of my publishing these early results is to afford that explanation, and 

 to enable me to procure a considerable variety of materials to work 

 upon. I especially want sets of family photographs, all as nearly as 

 possible of the same size and taken in the same attitudes. The size I 

 would suggest for family composites is that which gives one-half of an 

 inch interval between the pupil of the eye and the line that separates 

 the two lips. The attitudes about which there can be no mistake are : 

 full face, an exact profile, say, always showing the right side of the 

 face, and an exact three-quarters, always showing the left ; in this, the 

 outer edge of the right eyelid will be only just in sight. In each case 

 the latter should look straight before him. Such portraits as these go 

 well into cartes de visite, and I trust that not a few amateur photogra- 

 phers may be inclined to make sets of all the members of their family, 

 young and old, and of both sexes, and to try composites of them on the 

 principles I have described. The photographs used for that purpose 

 need not be in the least injured, for the register marks may be made in 

 the case into which they are slipped, and not in the photographs them- 

 selves. Nature. 



1 Example : There are 5 brothers or sisters and 5 cousins whose portraits are avail- 



100 

 able ; the total period of desired exposure is 100 seconds. 5 x 4 + 5 25 ; ~KT ^ ! 



which gives 4x4 = 16 seconds for each brother or sister, and 4 seconds for each cousin 

 (5x16 + 5x4= 100). 



