Pine Bluff daily graphic., 1907-06-13
PICTURES OF
 LISTENING Have Been Taken by the Smithsonian Institute at Washington and Are At- tracting Much Attention.
IMMIGRANTS ID E A
Gave Dane Aid and He Is Now Experi. menting for the Smithsonian In- stitute-Inyisible Lightning Dis- c0veTy.
Special to Graphic.

OpcCldl LO 0AopAAS'
 Washington, June 13.-Photo- graphs of lightning flashes are not new, but such pictures as recently have been taken under the auspices of the Smithsonian Institution have attracted unusual attention in the scientific world.
 Curlously enough, the investiga- tions which have been conducted along this line were brought about almost through accident. A year or so ago, letter was received by the secretary of the Smithsonian lnquiring for a publication of the experiments. It was couched in quaint English and written in a foreign hand. It's author was Alex Larsen, who short time before had arrived in this country as an immigrant from Denmark. In his letter Larhen mentioned incidental ly, that he had taken some photo graphs of lightning by holding small camera in his hand and re- volving it from side to side. He enclosed proof of one of his pie lures and inquired whether it was of any scientific value.
 The idea of taking pictures of lightning with moving camera was an entirely new one to the officials of the institution. They opened correspondence with Lar sen and found that he was more than ordinarily well versed in science, having made study of chemistry, physics and mechanical and electrical engineering at night school in Denmark His ma terial resources were limited and the apparatus he used was neces- sarily crude. He had conducted his experiments at odd moments, hay ing to do manual labor to eke out an existance.
 lhez Smithsonian official deemed young, Larsen worthy of assistance and they provided him with an ex- eellent photographic apparatus and gave -f11m a. sum of money with "hlch to continue his experiments ana to pay, in part, for his SUD- port The results of this compara- lively small outlay have been not- able. Young Larsen constructed :, revolving table which may be kept Ill constant motion by an electric motor. On this table he set sev. efal cameras in such positions that one of them would catch any flash or lightning that might appear oii tue entlre circle of the horizon. avery flash of lightning was inn printed on one or another of the piates exposed. A perpendicular nash showed broad sheet on the plate. The time of the flash was determined from the known width of the sheet on the plate. and the Known motion of the table on which the camera was set.
 MT. Larsen has determined by his experiments that flash of hshtnns is not one single vibra- 'ioh' but is composed of numerous small flashes or "rushes." On some o1 the negatives developed if was found that single flash was composed of as many as forty rushes." How rapidly these rushes must have followed each other may De imagined from the fact that the Hash was of fraction less than nall a seconds duration. Accord ing to calculations made by Mir, Larsen, the rushes vary in dura- ton rom three one-hundredths of a second to two one-thonsandtbs n, second
 In the opinion of the Smith -sonlan experts, the most remark able result of Larsen's experiment. IS that he has determined finally that there is a "black rush" i, the lightning flash, that is, rusl that is not discernable to the eve Larsen says such flash woul, appear black on a partially illumi mated background, or be invisible
 It mas been demonstrated, there lore, that there is invisible ligh,
 ning' paradexical as that may seen
 MT. Larsen is continuing his e,