PHENOMENA OF PLANT-LIFE. 43 



timber seasoned. Some have endeavored to account for this 

 phenomenon by referring it to the effect of the wind, but 

 it is frequently seen on trees which grow in sheltered situa- 

 tions. The timber of Pinus longifolia, a valuable tree of 

 Northern India, is often rendered worthless by this habit of 

 growth, and while such trees are more numerous in some 

 regions than in others, they are found irregularly scattered 

 among those which do not exhibit this abnormal structure. 

 (Fig. 43.) 



The surprising phenomena of pressure and suction exerted 

 upon mercurial gauges attached to the trunks and roots of 

 such trees as bleed or flow from wounds in the spring, which 

 were described in the paper presented to the Board last year, 

 gave abundant encouragement for further investigation. Ac- 

 cordingly, numerous experiments have been undertaken and 

 some thousands of observations recorded, which have been 

 tabulated, and are appended in as compact a form as possible. 

 To accomplish so much work as is here represented in a single 

 season, required the cordial cooperation of a considerable 

 number of persons. It is proper that the names *of those 

 officers and students of the College who have faithfully and 

 intelligently labored to accumulate these facts should be an- 

 nounced in connection with what they have done. If all who 

 enjoy the privileges of students in natural science would 

 exhibit the same enthusiasm for the acquisition of new truths, 

 they would thereby not only improve themselves but increase 

 the common stock of knowledge with a rapidity altogether 

 unprecedented. 



Prof. Levi Stockbridge has made nearly all the observations 

 upon the flow of sap in the sugar maple, and has faithfully 

 kept the record of the variations of pressure in the mercurial 

 and water gauges on the sugar maple, the red maple and the 

 butternut, which have been noted three or more times daily 

 for several months. 



Prof. S. T. Maynard has devoted much time to the care of 

 the squash whose unparalleled performances in harness attest 

 unmistakably its health and vigor. He has also kindly as- 

 sisted in the preparation of gauges, and in every way in which 

 his services were needed. The drawings for the cuts repre- 

 senting the squash and the apparatus used in the experiments 



