July 6, 1900.] 



SCIENCE. 



37 



found also in lines running up and sometimes 

 down the rachis from the glands. These are 

 very active during the rapid growth of the 

 frond, their activity ceasing on the attainment 

 of maturity. The secretion, which is very 

 abundant, is formed independently of bleeding 

 pressure, and the fluid is thick and syrupy. So 

 rapidly does it accumulate that one may notice 

 the increase in the size of the drops with a hand 

 lens. The secretion escapes through modified 

 stomata similar in form to the water-stomata of 

 Tropeolum. The glandular tissue beneath ex- 

 tends deeply into the cortical mass of the peti- 

 ole ; its cells are small and contain chlorophyll. 



Small ants, and one honey-gathering dipter- 

 ous insect were noticed visiting the glands ; 

 none were seen to be gnawed by the insects. 

 As F. Darwin observed, the plant has few nat- 

 ural enemies or none, and the teleological in- 

 terpretation must be sought in the internal 

 economy of the plant, probably in connection 

 with nutrition. The abundant excretion of 

 sugar may be a carrier of or an accompaniment 

 to the excretion of some harmful substance. It 

 is noteworthy that up to the present time no 

 other Pteridophyte has been reported to be pos- 

 sessed of nectar-secreting organs. The plants 

 on which the observations were made grew near 

 Bantam Lake, Litchfield, Conn. 



Dr. Britton remarked on a young tree of the 

 Swamp Spruce, Picea brevifolia Peck, found 

 during the day in a sphagnum bog near Litch- 

 field, and stated that this was probably the 

 most southern known station for this species in 

 New England. The short glaucous leaves and 

 nearly glabrous twigs readily distinguish this 

 tree from the Black Spruce, P. Mariana. 



Mrs. Britton exhibited specimens of the red- 

 flowered Columbine of the Litchfield region, 

 and remarked on its growth in open fields and 

 the pubescent character of the plant, differing 

 in these features from the plant of the vicinity 

 of New York, which inhabits rocky ledges and 

 is nearly or quite glabrous. She noted that the 

 pubescent plant is also abundant in fields on the 

 Pocono plateau of Pennsylvania. 



A vote of thanks was tendered to Dr. Allen 

 for his most generous and agreeable hospitality. 

 N. L. Britton, 

 Sec'y pro teni. 



CURRENT NOTES ON METEOROLOGY. 



CLIMATE AND THE ICE INDUSTRY. 



The practical use made of nocturnal radia- 

 tion for the preparation of ice in certain parts 

 of India has long been well known. The method 

 pursued there is to expose shallow porous 

 earthenware dishes filled with water and rest- 

 ing on rice straw, loosely laid in a small exca- 

 vation on the surface of the ground. When the 

 conditions are favorable, ice is formed in con- 

 siderable quantities, even when the temperature 

 of the air is 15° or 20° above freezing. A case 

 of a somewhat similar kind is noted by O. H. 

 Howarth, in a paper on ' The Cordillera of Mex- 

 ico and its Inhabitants,' in the Scottish Geograph- 

 ical Magazine for June. In one of the highest 

 valleys in Oaxaca, at an elevation of 8000-9000 

 feet, a flourishing ice industry was discovered. 

 It is stated that the ground is covered with a 

 large number of shallow wooden troughs, which 

 are filled with water, and during the winter 

 nights are covered with a film of ice of not 

 more than one-eighth of an inch in thickness. 

 This ice is removed in the morning, shovelled 

 into holes in the ground, and covered with 

 earth. Under these conditions the ice consol- 

 idates, and is then cut out in blocks and sent 

 down by mules to the towns, where a ready 

 market is found at all seasons. 



FROST FIGHTING. 



'Frost Fighting,' is the title of Bulletin No. 29 

 of the United States Weather Bureau, prepared 

 by A. G. McAdie, local forecast oflicial at San 

 Francisco. The question of protection against 

 frost has been very carefully studied by the 

 Weather Bureau ofiicials in California during 

 the past four years, and every effort has been 

 made to forecast coming frosts, and also to in- 

 vestigate the best methods of protection. Mr. 

 McAdie says that ' ' the experience of the past 

 three years warrants the statement that the 

 loss due to frosts in California, hitherto con- 

 sidered unavoidable, can be prevented, and 

 that unless extreme conditions, by which is 

 meant lower temperatures by 5° than have ever 

 yet been experienced in this State, occur, the 

 citrus fruits of California can be successfully 

 carried through the period when frost is likely." 

 The formation of frost is found to be very 



