ANALYSIS, REFINING, AND COMPOSITION. 63 



feature, inasmuch as unfortunate odor has been the greatest objection to a 

 large use of this class of material in the past, and at the present time it is 

 the main cause of the prejudice against it. 



From the standpoint of working qualities there is, as you will note, quite a 

 decided action in slowing up the drying. I am not aware as to just what 

 causes this, nnd of course for many purposes it would not be serious. There 

 are many uses, however, for quick-drying color where the time requirements 

 are so imperative that none of these materials could be used. We do not un- 

 derstand why the same measure of influence on the drying does not show up in 

 connection with varnishes, but as a matter of fact it does not. 



We should say that your sample No. r> is decidedly better in generul charac- 

 teristics than any wood turpentine we have ever seen. In every point, except- 

 ing the drying in quick-drying black, it shows up entirely equnl to straight 

 turpentine. 



Nos. 1, 2, 4 are satisfactory as wood turpentines, and would be usable for 

 all purposes for which high-grade wood turpentine is at the present time 

 usable. 



The sample tested under B represents wood turpentine, of which we have used 

 a considerable quantity and with which we have had practically no trouble 

 excepting from the standpoint of odor. 



It is impossible at the present time to substitute wood turpentine for a pure 

 spirits in many places on account of the stronger odor, and from his stand- 

 point your sample No. 5 looks particularly interesting. 1 



REPORT 2. 



Sample was taken from each can and compared in laboratory with pure 

 gum spirits. The only objection raised was the decidedly objectionable odor 

 in the No. 3 as well as the objectionable odor and slow evaporating in No. 5. 



The samples were then tested as a thinner or solvent in an ordinary house 

 paint and the same results obtained. The man applying the goods objected to 

 the odor of both Nos. 3 and 5. 



I then melted a batch of varnish and divided it into six equal parts, thinning 

 five of these with the five samples of wood turpentine and the sixth part with 

 pure gum spirits, 2 so that the body or base of all are identical. 



After filtering and settling these six varnishes were submitted to practical 

 tests by our head tester, who reports as follows : 



Working with brush Good. 



!Nos. 3 and 6 best. 

 Nos. 1, 2, and 4 fair. 

 No. 5 slow. 



Color all up to standard. Odor: Nos. 3 and 5 strong odor; No. 3 most ob- 

 jectionable; Nos. 1, 2, and 4 fair; No. 6, sweet. 



In having this test made we took great care both in making and testing 

 the varnish. The man who tested did not know that he was not testing a 

 regular run of six batches of one of our standard varnishes, which shows con- 

 clusively that he was doing his duty in an unbiased manner, and, as you will 

 note, his report on odor corresponds with both laboratory report and test made 

 by painter. 



REPORT 3. 



Material or fsubjcct. Wood turpentine Nos. 2, 3. 4, and 5 from United States 

 Department of Agriculture, Forest Products Laboratory. 



1 The large variation in the drying properties found by the quick-drying hlr.ck K^t 

 indicated that this test offered a fairly simple method of determining the effect of the 

 removal of the heavy oils on the drying properties. Small samples of each of the five 

 turpentines were redistilled so as to prepare samples containing no heavy oils, and these 

 special samples were submitted for the drying test. It was reported that the time of 

 drying of all the samples had been brought closer together and closer to that of gum. 

 turpentine. 



2 Reported as No. 6. 



