142 



THE POPULAR SCIENCE MONTHLY. 



Atmospheric Nitrogen as Food for 

 Plants. — The results of experiments at the 

 agricultural stations at Middletown and 

 Mansfield, Conn., are in favor of the value 

 of atmospheric nitrogen as a food for plants. 

 The conclusions are deduced from them by 

 Prof. Atwater that many, if not most, of 

 the leguminous plants are able to and do ac- 

 quire large quantities of nitrogen from the 

 air during their period of growth ; and that 

 there is some connection, not yet defined, 

 between root -tubercles and the acquisition 

 of this aliment. The cereals with which ex- 

 periments have been completed have not 

 manifested the same power, and they do not 

 have such tubercles as are formed on the 

 roots of the legumes. The addition of soil in- 

 fusions did not seem necessary for the pro- 

 duction of root-tubercles. The size and vigor 

 of the plants, and their gain of nitrogen from 

 the air, seemed to be proportional to the abun- 

 dance of root-tubercles in the experiment. 

 Losses of nitrogen sometimes occurred, but 

 always in cases where there were no root-tu- 

 bercles. The ability of legumes to gather 

 nitrogen from the air helps to explain the 

 usefulness of certain members of the family 

 as renovating crops, and enforces the im- 

 portance of using them to restore fertility to 

 exhausted soils. Conversely, the loss of ni- 

 trogen suffered by some other crops, such as 

 oats, suggests a possible reason why they 

 should appear to be " exhausting " crops. 



Coffee in Brazil.— The cultivation of cof- 

 fee has been greatly extended in Brazil dur- 

 ing recent years, chiefly in the southern 

 provinces. The planting is done on freshly 

 cleared ground after a single crop of Indian 

 corn has been raised from it, either by sow- 

 ing the seed directly or often by transplant- 

 ing from slips grown in nursery rows. Dur- 

 ing the earlier years corn, beans, and occa- 

 sionally sugar-corn are grown between the 

 rows. The coffee-plant usually begins to 

 bear at the fourth year from the nursery, or 

 the fifth or sixth year from the seed. The 

 tree is supposed to reach its prime at ten 

 years old, becomes practically sterile at twen- 

 ty, and may by care be kept in bearing for 

 forty years. The extremes of the flowering 

 season are from August to January. The 

 berry begins to form in November, and to 

 ripen in April or May, when the harvesting 



begins. This is done by hand, and gener- 

 ally very carelessly. The berries are washed, 

 dried, and put through various processes of 

 cleaning for the market ; what is called 

 " washed " coffee is put through a different 

 process, in which much of the treatment is 

 given under water. 



Objeet-Stndies in Botany. — Prof. Bessey 

 some time ago urged teachers of botany to 

 give a more intelligent direction to the col- 

 lections which their pupils will make during 

 the season of study. The usual course is to 

 gather a surplus of the showy flowers which 

 are the most easily studied, and neglect the 

 others, of which less is known. The teacher 

 should take special pains to point out the 

 features of interest in the funguses, etc., 

 which the student may bring in. Let him 

 direct attention to the pores, on the walls of 

 which the spores are developed — to the 

 closely interwoven threads of the body of 

 the fungus. When a spotted strawberry- 

 leaf is brought in, let him tell something, 

 if it be but little, about the cause of the 

 spots ; and let the pupil be taught to look for 

 similar spots on other plants, and to study 

 them. Do so with lichens, with pond-scums, 

 with green slimes, with mosses, with liver- 

 worts — in fact, with whatever is brought in 

 by the sharp-eyed young collector. " He 

 must be a poor teacher indeed who can not 

 suggest something to his pupil about a toad- 

 stool or a puff-ball. It is not necessary to 

 know the species or even the genus to which 

 a plant has been assigned in order to be able 

 to make valuable suggestions to one's pu- 

 pils." 



Contributions to the Geology of Staten 

 Island. — Dr. N. L. Britton has reported to 

 the Natural Science Association of Staten 

 Island concerning observations that lead him 

 to consider that the serpentine and talcose 

 rocks forming the main ridge of the island 

 were derived from magnesian limestone and 

 hornblende or tremolite strata. The rocks 

 were doubtless originally deposited in a con- 

 formable sequence, but the serpentines were 

 left on top in the folding of the strata. The 

 hypothesis of a southwestward extension of 

 the crystalline rocks across New Jersey has 

 been confirmed in a well-boring at Perth Am- 

 bov. Considerable additions to the fossil 



