Prune Cluster After First Thinning
This is the same cluster of prunes shown in the preceding picture, after the cluster has been partially thinned by tapping with the rubber hose. The second, or hand thinning, will take place in a week or so, at which time one-third to one-half of the prunes here shown will be removed.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 5 Chapter 3