Aiigtist 19, 1S80] 



NATURE- 



i7i 



product may be dissolved under pressure and at mode- 

 rately high temperatures in camphor, and that on cooling 

 a hard, compact mass closely resembling ivoiy' is pro- 

 duced. This observation furnished the starting-point in 

 the manufacture of " Celluloid," a substance which has 

 already been put to many and varied uses, and promises 

 to be of much importance in the future. 



In the process of Tribouillet and Besauc^le — patented 

 in January, 1879 — the raw material, consisting of paper, 

 linen, cotton wool, hemp, or white wood, is dried at 

 100°, and is then nitrated in vessels of glass, clay, or 

 glazed sheet-iron, furnished with a double bottom, between 

 the parts of which water is constantly flowing. The 

 nitrating acid consists of a mixture of 3 parts concen- 

 trated sulphuric acid (sp.gr. = i'S34) and 2 parts concen- 

 trated nitric acid, containing nitrous acid. The dry and 

 finely-divided material is first treated with acid which has 

 been already once used for nitrating ; the materials are 

 mixed for ten or fifteen minutes by the help of a kind of 

 trowel ; the mass is pressed in a glazed iron cylinder 

 with perforated sides and bottom, through which the acid 

 runs out. The material is again treated with a fresh mix- 

 ture of acids in the proportions already mentioned ; it is 

 then washed with water in a series of wooden vessels 

 with perforated bottoms placed one beneath the other on 

 an inclined plane. The last particles of acid are removed 

 by washing with very dilute soda or ammonia, and again 

 with water. The material is then dissolved in appropriate 

 solvents, from which it is again recovered in a paste-like 

 form, by distilling off the solvent. 



For making artificial ivory and similar opaque sub- 

 stances, about 100 parts of the prepared nitro-cellulose 

 are intimately mixed with from 42 to 50 parts of very 

 finely-divided camphor, and the mixture pressed in a 

 warm press, into which steam is conducted, and which is 

 connected with a moist chamber wherein the fumes from 

 the press are condensed. After being for some time in a 

 warmer press, the material is dried in a chamber contain- 

 ing calcium chloride or sulphuric acid, and connected 

 with an air-pump. 



Other manufacturers appear to mix ivory-dust, nitro- 

 cellulose, and camphor, and to press the mixture when 

 moist, heat it with ethyl nitrite in a closed vessel until 

 perfectly homogeneous, and distil oft" the nitrite. 



Celluloid is a hard, perfectly homogeneous substance, 

 which is not attacked by ordinary reagents (it dissolves 

 slowly in cold concentrated sulphuric acid), cannot be 

 easily broken, and becomes plastic at about 125°. It may 

 be obtained in thin layers o'-, millims. in thickness, 

 which may be encrusted on wood, marble, &c. At about 

 140° celluloid suddenly decomposes, emitting a reddish 

 vapour ; this liability to complete decomposition may be 

 prevented by washing the celluloid with sodium sihcate 

 solution and then immersing it in a solution of sodium 

 or ammonium phosphate; thus treated, the material is 

 non-inflammable. 



If colouring materials be mi.xed with the celluloid 

 during the manufacture, artificial coral, amber, malachite, 

 and lapis lazuli may be prepared. 



Celluloid is an admirable material for forming the backs 

 of brushes, handles of knives or umbrellas, combs, play- 

 things for children, &c. ; it is also employed in America 

 as a substitute for linen in the manufacture of collars, 

 scarves for the neck, &c. Articles made of it may be 

 washed with soap and a brush, and are practically 

 indestructible. M. j\I. P. M. 



L. F. DE POURTALES 

 r (^ UR readers will be glad to have the following further 

 L ^-^ notice of the late Count Pourtales from his inti- 

 mate friend and colleague. Prof. A. Agassiz.— Ed.] 



Louis Franqois de Pourtales died at Beverly Farms, 

 Massachusetts, in the fifty-seventh year of his age, on 



July 17, iSSo. Spite of a magnificent constitution and a 

 manly vigour of body and mind which seemed to defy 

 disease and to promise years of activity, he sank, after a 

 severe illness, under an internal malady. 



Educated as an engineer, he showed from boyhood a 

 predilection for natural history. He was a favourite 

 student of Prof Agassiz, and when his friend and teacher 

 came to America in 1847, he accompanied him, and 

 remained for some time with the little band of naturalists 

 who, first at East Boston, and subsequently at Cambridge, 

 shared his labours. 



In 1S48 Pourtales entered the U.S. Coast Survey, where 

 his abihty and indefatigable industry were at once recog- 

 nised, and he remained attached to that branch of our 

 public service for many years. He then became deeply 

 interested in everything relating to the study of the bed 

 of the ocean. Thanks to the enlightened support of the 

 then Superintendent of the Coast Survey, Prof. Bache, 

 and of his successors, Prof. Peirce and Capt. Patter- 

 son, he was enabled to devote his talents and industry to 

 the comparatively new field of " thalassography " and the 

 biological investigations related to it. The large collec- 

 tions of specimens from the sea-bottom accumulated by 

 the different hydrographic expeditions of the U.S. Coast 

 Survey were carefully examined by him, and the results 

 were published, in advance of their appearance in the 

 Coast Survey Reports, in Peterniann^s JMittheilungen, 

 accompanied by a chart of the sea-bottom on the east 

 coast of the United States. 



So interesting and valuable were the results obtained, 

 not only as an aid to navigation, but in their wider 

 bearing on the history of the Gulf Stream and on the 

 distribution of animal life at great depths, that in 1866 he 

 was sent out by Prof. Peirce, then superintendent of 

 the Coast Survey, to continue these investigations on a 

 larger scale. During 1866, 1S67, and 1868 he was in 

 charge of the extensive dredging operations carried on by 

 the U.S. Coast Survey Steamer i?/i5/', acting-master Piatt, 

 along the whole line of the Florida reefs and across the 

 Straits of Florida to Cuba, Salt Key, and the Bahama 

 Banks. The results of these expeditions, published in 

 the Bidletiii of the Museum of Comparative Zoology, 

 excited great interest among zoologists and geologists. 

 M. Pourtales was indeed the pioneer of deep-sea 

 dredging in America, and he lived long enough to see 

 that these expeditions had paved the way not only for 

 similar English, French, and Scandinavian researches, 

 but had led in this country to the Hasslcr, and finally to 

 the Blahc expeditions, under the auspices of the Hon. 

 Carlile P. Patterson, the present Superintendent of our 

 Coast Survey. On the Hasslcr expedition from Massa- 

 chusetts through the Straits of i^Iagellan to California, 

 he had entire charge of the dredging operations ; owing 

 to circumstances beyond his control, the deep-sea explo- 

 rations of that expedition were not as successful as he 

 anticipated. 



At the death of his father M. Pourtales was left in an 

 independent position, which allowed him to devote himself 

 more completely than ever to his zoological studies. He 

 resigned his official connection with the Coast Survey 

 and returned to Cambridge, where he became thenceforth 

 identified with the progress of the Museum of Comparative 

 Zoology. To Prof. Agassiz his presence there was in- 

 valuable. In youth one of his favourite pupils, through- 

 out life his friend and colleague, he now became the 

 support of his failing strength. 



The materials of the different deep-sea dredging expe- 

 ditions above-mentioned had been chiefly deposited at 

 the Museum in Cambridge, and were thence distributed 

 to specialists in this country and in Europe. A large 

 part of the special reports upon them have already 

 appeared. M. Pourtales reserved to himself the Corals, 

 Halc)onarians, Holothurians, and Crinoids. A number 

 of his papers on the deep-sea corals of Florida, of the 



