among which probably the most important are sodium, potassium, lithium, calcium, strontium, barium, cesium, rubidium, magnesium, aluminum, beryllium, cerium, radium, tantalum, thallium, titanium, uranium, and vanadium.
New-Found Bacteria Deadly to Insects. Several new diseases of insects, due t o Ibacteria that have hitherto not been observed by scientists, have heen reported t o the ~ m e r i c a nMuseum of Natural History by F. Martin Brown, of St. George's School a t Newport. Three species of bacteria and one mold were isolated from a number of dead woadflies found on an asparagus stalk. Experiments showed that one, which has been named "Bacillus lutzae," in compliment to Dr. F. E . Lutz, entomologist of the museum, , is fatal t o houseflies. Another germ proved lethal t o an insect that gives people pleasure instead of doing them h a m . I t kills the common hright Monarch butterfly over night. Mr. Brown conjectures that this disease may he the cause of the decline in numbers of this butterfly in the East during recent years. The researches were carried on a t the community hospital a t Tuxedo, N. Y., with the maperation of Dr. Edward C ,Rushmare and Miss Margaret Stevens.-Science Service Mosquito-Killing Oil Helped by Tar Acids. "More dead skeeters per gallon" is the aim of Dr. Joseph N. Ginshurg of the New Jersey Agricultural Experiment Station, who reported on his researches with fuel oil as a mosquito-killer before the meeting of the New Jersey Mosquito Extermination Association. Oil spread on water t o kill mosquito "wigglers" is a standard remedy for the stingingpests and one widely employed, but when vast areas of swampy land have t o be treated, as they do along the Atlantic Coast, the spread per gallon becomes a n important thing, Dr. Ginshurg reminded his hearers. In his laboratory experiments he found that the addition of certain organic acids derived from tar would make a gallon of oil blanket half again as much water as could be covered by a like quantity of untreated oil, and that the acidified oil made conditions intolerable for mosquitoes for an appreciably longer time.-Science Sevice New Instrument Measures Tiny Electric Current. An electric current, so small that a t the pressure and price of the ordinary house lighting current it would cost less than a faur-hundred-billionth of a cent, can be measured with the aid of a new instrument just developed in the standardizing laboratory of the General Electric Company a t Lynn, Massachusetts. I t is known as a thermionic microammeter, and a current of a ten-millionth of an ampere is sufficient to carry the pointer completely across the dial, while a single division on the scale represents one five-hundredth of this amount. The instrument will be useful in measuring the minute currents in insulators and radio tubes, hut it is stated that the chief application foreseen a t present will be in combination with a photo-electric cell for accurate measurements of illumination. At present the intensity of electric lights, for example, is measured by visually eamparing them with another light of standard brightness. The electrical eye, the phatoelectric cell, may now replace the human eye in this work, for the cell converts light energy into tiny electrical currents, which may be easily measured with the new instrument.-Science Service
