314 PLUM. 



injurious. Trees should be daubed not later than the middle 

 of October. A good daub should be used, and looked after 

 that it is kept moist and adhesive, otherwise moths will cross 

 over it."— (J. M.) 



These points need very careful attention, for though it is 

 very possible that on old trees (where the thickness of the 

 bark protects the vital layer of young bark and wood forming 

 beneath almost as effectually as if a cradle of pieces of cork 

 was fastened round the tree) there may be no damage caused 

 by tarring, this is very different to making use of it on young 

 trees, where, as it has been very well described, it fairly 

 " 'Waterproofs " the sodden tissues, and I believe myself that 

 tar should not be used on young bark, and in any case should 

 be used with care and caution. 



With regard to cart-grease itself, so far as a regular form 

 can be given, it appears to be usually compounded of tallow, 

 palm oil, and soft-soap, or, what comes to the same thing, 

 tallow, palm oil and water, and caustic soda. The following 

 notes of the ingredients of some of the mixtures or prepara- 

 tions commonly made use of or sold under the names of 

 "waggon-axle" or "railway grease" may probably be of 

 service in showing the ingredients of the ordinary compo- 

 sitions, and also that some of the additions or special makes 

 for suitable special machine use are by no means what can be 

 recommended for spreading at haphazard on living vegetable 

 tissues.* 



Of two kinds of railway or waggon grease mentioned in 

 the work below quoted, one consists essentially of a mixture 

 of a more or less perfectly-formed soap, water, carbonate 

 of soda, and neutral fat, whilst the other is a soap of lime and 

 rosin oil, with or without water. Frazer's axle grease con- 

 sists of rosin oil of various numbers, saponified with a solution 

 of sal- soda in water and softened lime ; and these two rosin 

 recipes are apparently very similar to a composition used with 

 success at Toddington. 



Some other mixtures are merely of greasy or soapy com- 

 positions ; one is of tallow and palm oil melted together and 

 mixed with soda ; two others are of palm oil and tallow for 

 the foundation, mixed respectively with sperm oil and caustic 

 soda, or with rape-seed oil and soda; another, the " Austrian 

 railway grease," is of tallow, olive oil and "old grease." 



So far, there would be nothing deleterious to bark beyond 

 what injury may occur from grease gradually soaking into the 

 tissues, but a preparation of " axle grease," composed of black 

 oil or petroleum residue, animal grease, powdered rosin added 



* See pp. 376 — 379 of paper on "Lubricants " in 'Workshop Eecipes,' by 

 C. W. Warueford Lock, published by E. & T. N. S^jon, Charing Cross, Loudon. 



