X 
THE VOYAGE OF H.M.S. CHALLENGER. 
tlic proposed publication were arranged. For the past ten years the work 
has been continuously carried on, and in the interval we have published 
preliminary papere dealing with our results.^ 
At the outset it was proposed to give a detailed description of every 
sample of deposit from depths greater than 100 fathoms, together with all 
that was known of the physical and biological conditions of the waters at 
the Stations from which the specimens were obtained. Nearly all the 
Challenger siimi)les, and a very large number of samples collected by other 
Expeditions, were in fact thus examined and largely prepared for publi- 
cation, with names of the species of organisms and all other particulars. It, 
however, became necessary to curtail the descriptions, and to limit them to 
the Challenger collections, so that the work ultimately assumed its present 
form. 
The details with reference to the various samples of deposits collected by 
the Expedition are presented in tabular form in Chapter II. The more general 
conclusions and descriptions are given in a series of chapters dealing with 
the composition and distribution of the different types of deposits, and in the 
preparation of these chapters we have made use of all the materials in our 
possession. Professor Renard thinks it should be stated that Chapter IV., 
dealing with the materials of organic origin, has been written wholly by 
Mr. Murray. 
We are much indebted to our friends. Sir William Turner and Mr. Robert 
Irvine, for reading ditlerent portions of the proofs, and giving us the benefit 
of their suggestions, and we have to thank the various analysts and other 
scientific men for valuable hints during the progress of the work. We desire 
to acknowledge our indelHcdness to all those assistants who have aided 
us in the practical examination of the deposits, especially to Mr. Frederick 
Pearcey, who accompanied the Expedition and was afterwards assistant in 
the (’hallcngcr Ofiicc, and to Mr. James Chumley, who not only helped in 
the practical examination of the specimens, but has also rendered great 
assistance in the j»rei)aration of this volume for the press. 
’ “On the Mirrrwcojiic Characters of Volcanic Ashcfl and Cosmic Dust, and their Distrilmtion in Deep-Sea 
Dr]Miu,” I‘rnr. Hoy. Sor. Kdin., vol. xii. pp. 474-40r), 1884; “On the Nomenclature, Origin, and Distribution of Deep- 
Sea IVpcMiU,'' ihid., pp. 495-520. 
