OBSERVATIONS UPON THE PHENOMENA OF PLANT-LIFE. ^27 



maple, and the butternut, which have been noted three or more times daily 

 for several months. 



Prof. S. T. Mayuard 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 assisted in the preparation of gauges, and in every way in 

 which his services were needed. The drawings for the cuts representing the 

 squash and the apparatus used in the experiments with it, as well as for those 

 relating to the specimens of elm, were furnished by him. 



For the very convenient form of stopcocks used in the mercurial gauges we 

 are indebted to the ingenuity of Prof. S. H. Peabody. 



Much credit is due to Mr. D. P. Penhaliow, a post-graduate student, for his 

 untiring devotion to the study of the squash vine, with which he spent many 

 days and nights, observing its mode of sfrowth and making complete micro- 

 scopical drawings of all its structure. He also adjusted gauges to several her- 

 baceous plants, and reported upon the pressure of their saps. He assisted in 

 finding the per cent of water in various species of wood at different seasons of 

 the year, and his pencil prepared all the drawings, except those already men- 

 tioned. 



Charles Wellington, B. S., assistant in the chemical laboratory, has under- 

 taken to determine the composition of various saps, and the efiect on them of 

 the advancing season. This important investigation is not yet completed. 



Mr. Walter H. Knapp, with great fidelity, furnished the material for the 

 table showing the amount of sap which flowed daily from each species. 



Mr. Atherton Clark made the observations on the water gauges, except that 

 on the sugar maple, on the mercurial gauges in the case of white birch root, 

 the apple root, and the three on the grape vine, one of which was thirty feet 

 from the ground. He also did much of the work relating to the time when 

 each species begins to flow. 



Mr. William P. Brooks began and carried out very thoroughly a series of 

 observations to learn precisely what species flowed, at what time in the season, 

 and how rapidly, visiting for this purpose about forty species daily for several 

 weeks. In some unaccountable manner, the memorandum book containing most 

 of his records has been lost, and so his report is incomplete. 



Mr. Henry Hague recorded the variations on the mercurial gauges upon the 

 four birches, one of them thirty feet from the ground; and on the hornbeam, 

 three times daily for many weeks. 



Mr. George R. Dodge attended to a series of experiments instituted to deter- 

 mine the circumstances which affect the flow of sap from the maples, and fur- 

 nished an excellent report. 



AMOUXT OF SAP. 



It has been said that all species of flowering plants will probably bleed from 

 some part, if wounded, at some time of their growth. This has not been 

 demonstrated, and some trees seem to have a wood so remarkably spongy and 

 retentive of moisture as to render it unlikely that they should ever flow. Much 

 effort has been made to arrive at the truth on this subject concerning our com- 

 mon forest trees by methods detailed below. 



About the middle of last March a large number of trees were selected and 

 prepared for observation, by boring one half-inch hole to the depth of two 

 inches into the wood and insertinga galvanized iron sap-spout, invented by Mr. 

 C. C. Post of Burlington, Vt, and well adapted for use in the sugar-bush. The 



