18 



SCIENCE. 



[N. S. Vol. IV. No. 79. 



which afterwards die, and the fruits split 

 and drop before maturing. It is an advan- 

 tage to withhold organic nitrogenous ma- 

 nures. The scab attacks lemons and sour 

 oranges and disfigures the foliage and fruit 

 by producing warts. It can be prevented by- 

 spraying with fungicides. Sooty mould is a 

 fungus following the attacks of insects and 

 fumigations to kill the insect prevents it. 

 Foot-rot is the most destructive malady and 

 is recognized by gum exudation at the base 

 of the tree. The cause is probably some mi- 

 nute organism and prevention is found by 

 cutting away the diseased parts and wash- 

 ing with fungicides. Melanose is a new 

 disease of all citrous fruits, not yet very 

 destructive, the cause of which is unknown, 

 but Bordeaux mixture is a satisfactory 

 remedy. 



COMBATTING CARNATION BUST. 



The growing of carnations is a large in- 

 dustry in this country, but is beset with 

 many vicissitudes not among the least of 

 which is the carnation rust. This trouble 

 has been under investigation at some of 

 the experiment stations, and before us lies 

 bulletin IS'o. 100, of the New York Experi- 

 ment Station, with the title as given above. 

 Mr. Stewart, the author, has tested the 

 germination of the spores of the rust fun- 

 gus in various substances, and finds, for 

 example, that a 1-100 solution of copper sul- 

 phate is much too weak to prevent germina- 

 tion. When common salt is used 1-45 is 

 the strongest solution in which the spores 

 can grow. The spores, on the other hand, 

 are remarkably susceptible to the action of 

 potassium sulphide, a 1-3,000 solution en- 

 tirely preventing germination. A similar 

 series of results was obtained by soaking 

 cuttings in the above solutions, those in 

 potassium sulphide being unharmed. At- 

 tempts to cure rusty plants by spraying 

 with fungicides failed, but good results 

 were obtained in preventing its appearance 



upon healthy plants. Eust, it has been 

 shown, will spread among mature plants. 

 It is important that carnation plants be 

 held up from the ground by inverted Y's 

 of wire netting. For unknown reasons, 

 some varieties are much more susceptible 

 than others to the rust. 



POTATO DISEASES UPON LONG ISLAND. 



In addition to his carnation investi- 

 gations Mr. Stewart has made a study of 

 potato diseases, the results of which appear 

 in Bulletin ~So. 101, of the New York 

 Station. In addition to the good results 

 following from spraying with the Bordeaux 

 mixture for the blights, notes are given 

 upon an internal browning of potatoes, the 

 cause of which is not determined. The 

 brown spots are entirely surrounded by 

 healthy tissue, and cultures made from the 

 discolored portions produced no growth. 

 Under the microscope the brown spots give 

 no clue as to the cause of the trouble, and 

 it would seem to be physiological and not 

 mycological in its origin. Field experi- 

 ments indicate that the browning is not 

 transmitted from seed to product, but the 

 discolored tubers are not the best to use 

 for planting. There are several stem 

 blights of potatoes, but Mr. Stewart finds 

 another which seems to strangle the plant 

 and working internally will be a difl&cult 

 one to check. A new fusarium {F. acum- 

 matum E. & E.) is reported. 



Byeon D. Halsted. 



EuTGEES College. 



SCIENTIFIC NOTES AND NEWS. 

 ASTRONOMY. 



A MEETING was held at Paris last month which 

 will be of the greatest importance to the prog- 

 ress of astronomical science. Each of the four 

 nations whose governments publish elaborate 

 astronomical ephemerides were represented at 

 this meeting. The object of the conference was- 

 the discussion of the best system of astronomi- 

 cal constants, with a view to the introduction. 



