VARNISH AND PAINT EXPERIMENTS. 43 



were quick-drying turpentines, while Nos. 2 and 4 were slow drying. 

 In general, therefore, more of turpentines Nos. 2 and 4 would be 

 required to thin a varnish to a desired consistency than of Nos. 1 and 

 3, but the resulting varnish should be slower in drying. It will be 

 observed as a matter of fact that No. 4 varnish, in which destruc- 

 tively distilled turpentine was used, is the thinnest varnish of all 

 and it was unnecessary to thin it further. 



On the whole, no definite conclusion can be drawn from the data 

 obtained by the experimenters on the handling and working of the 

 varnishes. This is not a criticism of those who at considerable pains 

 and inconvenience cooperated in the work. The unsatisfactory 

 character of the data arose in part through the difficulty of explaining 

 clearly in written directions exactly what experiments and what 

 information were desired. Had it been feasible for a representative 

 of the bureau to talk with and assist those actually doing the work, 

 more valuable information could doubtless have been ob tamed. 

 Of course the data could only be of value hi determining the relative 

 working qualities of the varnish thinned with the different turpen- 

 tines; but little information as to the appearance and durability of 

 the varnish was obtained. Opinions on this point must be based 

 on a later careful examination and study of the finished panels. 

 These panels were prepared four years ago. Since that time they 

 have been exposed in one of the office rooms of the bureau for from 

 12 to 18 months, and during the rest of the time have been stored, 

 protected from dirt and light. None has been exposed to the weather 

 at any time. 



Careful examination of these panels by a number of persons, includ- 

 ing master painters and others familiar with the use of varnishes, 

 discloses no marked deterioration of any of the coats nor any clear- 

 cut difference between the appearance of the several varnishes of the 

 same class, except that as a rule the varnish which the workman 

 was in the habit of using regularly looked a little better than the 

 others. This fact confirms the statement previously made that the 

 familiarity of the workman with the varnish influences the success 

 of his work, and, consequently, his opinion of the varnish. 



In addition to these experiments the same turpentines were 

 employed in thinning a white lead and linseed oil paint. No differ- 

 ence was observed in the working of the paint, and after drying all 

 painted panels presented the same appearance. There was no 

 difference in the color of the panels after one year. The interior wood- 

 work of the new building of the Bureau of Chemistry was painted 

 with zinc oxid and linseed oil thinned with other steam and destruc- 

 tively distilled turpentines. The workmen stated that the odor, 

 particularly of the destructively distilled samples, was unpleasant, 

 imt it did not seriouslv inconvenience them or make them ill. Both 



