Fig. 1. — Carbonic acid gas sprayer used in spraying experiments in 1907 and 1908 in Mrs. Smith's 

 vineyard, Paw Paw, Michigan. — Photo by Lon A. Hawkins. 



Fig. 2. — Mixing platform and geared traction sprayer used in spraying experiments in Mr. Towers 

 vineyard, Paw Paw, Michigan, 1908. — Photo by Lon A. Hawkins 



PLATE I. 



