Periodical Literature. 751 



salts, the active ingredients of a number of preservatives in the 

 market, Hke Kronol, Hylinit, MuroHneum, Montanin, Montan- 

 in fluat, Keramit, Keramyl and others. Many of these are sold 

 much higher than their antiseptic value, or contain the antiseptics 

 in an ineffective form ; and this fact has damaged the introduc- 

 tion of the fluorides. The sodium silico-fluoride, hov^ever, has been 

 extensively used by Rutgers, the 2% solution being made in hot 

 water (90° C). This makes wood also non-inflammable and can 

 advantageously be used for building timber. It is cheap. Curi- 

 ously enough, while weak solutions are antiseptic, fungi will grow 

 on concentrated solutions. This accounts for differences of opin- 

 ion as to its preservative use. 



Lastly, the author reports the experiments made in Austria with 

 fluoric acid itself. A zinc solution in hydro-fluoric acid (5%) was 

 first used in 1905 for telegraph poles, and in 1907, after satisfac- 

 tory experience, other fluorides were experimented with. The pro- 

 cess was similar to Kyanizing with 7 or 8 days immersion. The 

 salt cost about 10 cents a pound; a 3.7% solution of 5.5°Be being 

 used ; the absorption being about 4 lbs. in pine, and less than 2 

 lbs. in spruce. The cost is lower than for Kyanizing. 



An experiment to use the Boucherie process with this fluid 

 showed a much more rapid absorption than that of zinc chloride 

 or copper sulfate. A cubic foot required 16 lbs. of liquid leav- 

 ing about 4 to 5 oz. of the effective zinc salt in the wood or 2^ lbs. 

 for a 24 foot pole. This is about the same as it would be with 

 copper sulfate, but the antiseptic effect is as i : 5 in favor of the 

 fluor salt. The one objection is that the fluro salt attacks iron 

 vessels. To overcome this Malenkovic has invented a neutral 

 Chlor zinc-fluor-sodium process, which also prevents the leeching 

 out of the antiseptic. The interesting reactions of sodium fluoride 

 on zinc chloride in the dry wood body are explained. This process 

 has been considerably used in Austria. A few other experiments 

 with flurosalts are explained. 



Altogether a final judgment on the value and applicability of the 

 fluorides cannot yet be given, although they have been widely used. 

 Not less than a decade of experience suffices to give a verdict. 

 Systematic trials alone will lead to final judgment. 



Neuere Bestrebungen auf dem Gebiete der Holzkonservirung. Cen- 

 tralblatt fiir das gesammte Forstwesen. June, July, August, 1912. Pp. 265- 

 282, 3^1-333- 383-392. 



