34 



ZINC AS A NATURAL CONTENT OF APPLES. 



There is one point of interest to analysts which should not be over- 

 looked, viz, the possibility of zinc occurring naturally in plants. Ee- 

 searches of the past few years have shown naturally i^resent in plants 

 many metals which a few years ago were supposed never to enter the 

 plant organism. It is possible that fruit trees growingin localities where 

 zinc abounds may take this metal into their organs and fruits, as is the 

 case with copi)er and other rare metals sometimes found as natural 

 products in plants. It would be of interest to have fruits which grow 

 in localities where the soil is known to contain zinc examined for this 

 substance. If it should be found that plants have the power of absorb- 

 ing zinc, the presence of a mere trace of this substance in evaporated 

 apples would no longer be conclusive evidence of their having been 

 dried on galvanized iron wires. According to Filsinger (Chemiker- 

 Zeitung, 1894, vol. 18, p. 1239) there is already sufticient evidence on 

 record of the ability of plants to absorb zinc to render permissible the 

 question as to whether traces of zinc found in American evaporated 

 apples might not arise from the soil on which the orchards stand. 



SUBSTITUTION OF OTHER MATERIAL FOR GALVANIZED IRON WIRE IN 

 THE MANUFACTURE OF TRAYS. 



The results of the investigations which have been conducted show that 

 as long as galvanized iron wire trays are used for evaporating apples it 

 is not i^ossible to guarantee that the product shall be free of zinc. The 

 difficulty of securing even drying on wooden slats and the fragility of 

 trays made of cloth are sufficient reasons for excluding these two mate- 

 rials from consideration in the manufacture of drying trays. The fact 

 that aluminium is now manufactured at a very cheap rate suggested 

 the x)ossibility of using this material in making trays. With this pur- 

 pose in view, inquiries were directed to the Pittsburg Reduction Com- 

 pany in regard to the matter. This company showed a lively interest 

 in the question and kindly made, for the use of this Division, 12 square 

 feet of aluminium wire netting suited to the purpose required. This 

 wire at the present time costs 90 cents a pound, which would indicate 

 that the cost of the aluminium in a square yard would be a little over 

 60 cents. If there were much demand it could probably be made for very 

 much less. There would probably be one practical difficulty in the use 

 of the aluminium wire netting, arising from the fact that the strands not 

 being soldered together might be displaced by the wooden paddle which 

 is used in scraping the dried apples from the tray. The spaces in the 

 netting would thus become unequal and possibly in some cases large 

 enough to allow the slices to fall through. It has been suggested to use 

 perforated sheet aluminium for the bottoms of the trays. If this could 

 be done it would remove the difficulty mentioned above. 



Only experience will show how long the aluminium wire would with- 

 stand the action of the acids of the fruit. It is not probable, however, 



