106 



KNOWLEDGE. 



[September 1, 1896. 



tbe said cullors upon silk for windowes." Numerous mix- 

 tures of oils with resins were used until 1751, at which 

 date mention is first made of india-rubber or gum lastic as 

 an ingredient in the coating material. In 1814 Mr. E. 

 Galloway proposed the addition of powdered cork to plastic 

 india-rubber, in order to give a " certain elasticity " to the 

 combination, and cloth coated upon one side with this 

 mixture was brought into the market as a substitute for 

 floorcloth, under the name of " kamptulicon." This latter 

 was the immediate forerunner of our present linoleum, for 

 which wo are indebted to Mr. F. Walton. And now, at 

 the present moment, there are twenty-live factories in 

 operation, the greater number of them being in this 

 country, at which 12,000,000 yards of linoleum are 

 annually produced. 



The two main ingredients in the manufacture of linoleum 

 are cork and linseed oil, to which are added smaller quan- 

 tities of kauri gum, resin, and pigments of various kinds. 

 In the manufacture of bottle corks about one-half of the 

 cork is wasted, and this waste is the chief source of the 

 cork for linoleum. ]\Ir. Reid, however, adds that in the 

 cork forests of Algeria, etc., there is plenty of material 

 available which, while not suitable for bottle corks, would 

 answer admirably for linoleum. The cork waste, after 

 being freed from dust and other admixed substances by 

 means of a sieve with a rapid reciprocating motion, is 

 crushed. This sounds very simple, but, as a matter of fact, 

 the machinery required for the actual operation has to be 

 of a very special character, both on account of the elasticity 

 of cork and also because of the almost incredible rapidity 

 with which it blunts the hardest steel knife-edge. The 

 breaker reduces the cork to pieces of about the size of a 

 pea, in which state it is passed on to the grinding mill, 

 the latter being like an ordinary flour mill, but with stones 

 of lava, sandstone, or some other rough material. Cork 

 dust being excessively light, it quickly disseminates itself 

 through the air of the mill ; hence the utmost precautions 

 have to be taken to ensure the protection of all artificial 

 lights, and thus to prevent the explosive mixture of air 

 and cork dust being set on fire. Even with every pre- 

 caution, small explosions are sometimes caused by sparks 

 from the machinery. The author says, in fact, that 

 " speaking after considerable experience of both materials, 

 I would rather handle dynamite in bulk than cork in a 

 loose state." The dust has not yet been bleached success- 

 fully, i.e., the colouring matter adheres to it with such 

 tenacity that it can only be got rid of at the cost of lessen- 

 ing the strength and elasticity of the cork itself. Further, 

 although many experiments have been made with the view 

 of replacing cork by other substances— sawdust, spent tan, 

 peat, etc.— the resulting product possesses less elasticity 

 than when cork is used, and so wears out more rapidly. 



The next stage in the manufacture is the preparation of 

 what is technically known as " cement," the chief ingredient 

 of which is oxidized linseed oil. As everyone kaows, oils 

 are divisible into two classes, drying and non-dryino- oils, 

 the " drying " being brought about in the case of the first- 

 named by the absorption of oxygen from the air, and the 

 consequent transformation of the oil into a solid resinous 

 mass. For linoleum manufacture the linseed oil used 

 must be of good quality, and great care must be taken in 

 its treatment. The oil is first boiled, much as in the 

 manufacture of paints and varnishes. It has been found 

 that the process of drying is much facilitated by the 

 addition of a small quantity of the oxides of lead. The 

 boiled oil, after being allowed to deposit any sediment in a 

 settling tank, is pumped to the top of a high building, and 

 from thence allowed to flow over a number of pieces of 

 light cotton fabric known as "scrim," which hang vertically 



from iron bars. The air in the building being heated to a 

 temperature of about 100^ ]''ahrenheit, the layer of oil 

 which adheres to the surface of the scrim becomes rapidly 

 oxidized, or, in other words, it solidifies in the course 

 of twenty-four hours. This operation is repeated daily 

 for six to eight weeks, until a sufTicient number of 

 solidified layers of oil are deposited on the cloth, the mass 

 of oxidized oil having now a thickness of half an inch, and 

 being termed a " skin." The skins are then cut down and 

 ground between rollers. This plan of drying the oil is a 

 slow one, but more rapid methods have apparently not 

 been found to answer very well as yet, because there is a 

 danger of pushing the oxidation too far, in which case the 

 dried oil again changes into a liquid. 



To prepare the linoleum "cement" itself, the ground 

 oil is mixed with resin and kauri gum in different pro- 

 portions until the whole mass is homogeneous. And here 

 again fire has to be guarded against, as the cement has a 

 great tendency to heat and even to inflame if left in bulk 

 exposed to the air. The cement and cork dust are now 

 intimately mixed together by machinery in a series of 

 operations, various colouring matters being added at the 

 same time, according to the colour required for the finished 

 linoleum. This linoleum mixture is then rolled on to jute 

 canvas, to which it is made to adhere thoroughly. It 

 should be added that, instead of jute, wire gauze imbedded 

 in india-rubber is now being much used, especially for 

 linoleum intended for staircases. 



Linoleum, as prepared above, is of the same colour 

 throughout, and when an ornamented surface is required 

 the designs are printed upon it in oil paint. This, of 

 course, merely gives a surface colouring, which is liable to 

 wear out, and hence various plans have been and are 

 being tried with more or less success, whose object is to 

 produce a mosaic linoleum coloured throughout its entire 

 thickness. r>ut although such linoleums with inlaid colour 

 patterns have some advantages over the older kind, they 

 have also — up to the present time of writing — certain 

 disadvantages. 



Plain linoleum is usually made in two colours, brown 

 and red, of which the brown is the more elastic. The fact 

 that wet linoleum is stained when any article of iron is 

 placed upon it must often have been noticed, this being 

 due to the tannin contained lu the cork. In course of 

 time linoleum loses its elasticity and becomes brittle, this 

 being caused in the first instance by a change in the cement 

 induced by further oxidation, the cork remaining unaltered. 

 With regard to this the author of the paper remarks that 

 a more stable cement will probably be worked out in time 

 — possibly one derived from mineral oils, which have 

 little or no tendency to undergo oxidation in the air. The 

 linoleum industry, already a large one, will doubtless 

 continue to grow, and the manufactured product itself to 

 improve. Space will not permit of our entering into 

 further details regarding it here, and any reader who 

 wishes to know more about the subject is therefore referred 

 to Mr. Reid's able and interesting paper. 



THE SOOTY OR BROWN ALBATROSS. 



THE accompanying reproduction is from a photo- 

 graph very kindly supplied by the Hon. Walter 

 Rathschild. It was taken, as was the photograph 

 of the white-breasted albatrosses reproduced in 

 Knowledge for April, 1895, by Mr. Rothschild's 

 collector some years ago, in Laysan Island, on a sand- 

 bank in the Pacific off the Sandwich Islands. 



The sooty or brown albatross, sometimes called the 



