32 



Sample 14418 represents a laboratory j)roduct prepared from apples 

 purchased in the open market in Washington. These apples were put 

 through as nearly as possible the process employed in the manufacture 

 on a large scale, with the exception that they were dried on a tray made 

 of pure aluminium wire. The analysis, as was to be exi^ected, disclosed 

 not even a trace of zinc. 



EXAMINATION OF THE GALVANIZED IRON WIRE USED FOR MAKING 



THE TRAYS. 



It was thought to be a matter of interest to examine the galvanized 

 iron wire cloth used for making the trays employed in the manufacture 

 of evaporated apples. For this purpose samples were secured at the 

 factory of L. R. Eogers, Albion, N. Y., representing the unused mate- 

 rial and also that which had been constantly employed in the factory for 

 over live years. It would follow as a natural result from the nse of 

 this material that the zinc covering of the wire would gradually be dis- 

 solved by the acids of the apples and that in the end the iron core 

 would be practically denuded. In practice, however, it is found that 

 the constant rubbing of the trays to detach slices of evaporated apples 

 wears them out before the zinc is entirely removed. The results of the 

 analytical data which follow show, however, that a large percentage of 

 the zinc originally enveloping the iron core is dissolved in the course 

 of a few years. When the small quantity of zinc in a tray is taken 

 into consideration, it seems unreasonable to suppose that any marked 

 contamination of the product could ensue. Many thousand pounds 

 of fruit are evaporated on a single tray before it becomes unfit for use. 

 From the data which follow, however, it is seen that a tray having a 

 surface of one square yard carries about 2 pounds of zinc. This would 

 be suflBcient to contaminate 20,000 pounds of evaporated apples with 

 the average quantity of zinc oxid found therein in our analysis, viz, 

 10 milligrams per ,100 grams. The analytical data of the examination 

 of the wire cloth obtained by Mr. K. P. McElroy, follow : 



ex^lMinatiojst of wire cloth^ 



No. 14406. Unused wire cloth, from L. R. Rogers: 



Weight of 1 square yard of this cloth is 5.03 pounds. It is composed of 59.77 

 per cent iron and 40.23 per cent of zinc. On this basis 1 square yard would contain 

 2.02 pounds of zinc. 



No. 14407. Unused wire cloth (one year old), from L. R. Rogers: 



On handling this cloth particles of zinc scaled off freely. The weight of 1 square 

 yard is 3.08 pounds. It is composed of 60.65 per cent iron and 39.35 per cent zinc. 

 One square yard therefore contains 1.21 pounds of zinc. 



No. 14408 A. Wire cloth in use more than five years, from L. R. Rogers: 



Water extracts from this cloth traces of a soluble zinc salt, probably malate^ 

 and a little iron. The weight of a square yard of this cloth is 2.38 pounds. It is 

 composed of 80.68 per cent iron and 19.32 per cent zinc. One square yard contains 

 0.46 pound of zinc. 



