Waterbury evening Democrat., 1907-06-22
PICTURE OF LIGHTNING.
Alex Larsen of Denmark Helps the
 Government.

w dSltu6 lOhB S'y SaAS Photographs of lightning flashes are not new, but such pictures as re- gently have been taken under the auspices of the Smithsonian institu- tion, have attracted unusual atten- tion in the scientific world.
 Curiously 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 inQuir- ing for a publication of the institu- tion relating to photographic experi- ments. It was couched in quaint English and written in foreign hand. It's author was Alex Larsen, who short time before had ar rived in this country as an immigrant from Denmark. In his letter Larsen mentioned, incidentally, that he had taken some photographs of lightning by holding a small camera in his hand and revolving 1t from side to side. He enclosed proof of one of his pictures and inquired whether 1t was of any scientific value.
 The idea of taking pictures of lightning with a moving camera was an entirely new one to the officials Of the institution. They opened a correspondence with Larsen and found that he was more than ordin. arily well versed in science, having made study of chemistry, physics, and mechanical and electrical engin- eering at a night school in Denmark. His material resources were limited and the apparatus he used was nee. essarily crude. He had conducted his experiments at odd moments. having to do manual labor to eke out an ex- istence.
 The Smithsonian officials deemed young Larsen worthy of assistance and they provided him with an excel- lent photographic apparatus and gave him a sum of money with which to continue his experiments and to pay, in part, for his support. The results of this comparatively small outlay, have been notable. Young Larsen constructed a revolving table which may be kept in constant mo- tion by an electric motor. On this table he set several cameras in such positions that one of them would catch any flash of lightning that might appear on the entire circle of the horizon. Every flash of light ming was imprinted on one or anoth- CT of the plates exposed. A perpendi- cular flash showed broad sheet on / the plate. The time of the flash was determinable from the known width of the sheet on the plate and the known motion of the table on which the camera was set.
 Mir Larsen has determined by his experiments that a flash of light ming is not one single vibration. but is composed of numerous small fash es or "rushes." On some of the neg atives developed 1t was found that a single flash was composed of as many as forty "rushes." How rapidly these rushes must have followed each other may be imagined from the fac, that the flash was of fraction less than half a seconds duration. Ae- cording to calculations made by Mir Larsen, the rushes vary In duration from three one-hundredths of a sec ond to two one-thousandths of a sec. ond.
 In the opinion of the Smithsonian experts. the most remarkable result of Larsen's experiments is that he has determined finally that there is g "bIack rush" In the lightning flash that is, a rush that is not discernabls to the eye. Larsen says such a flash would appear black on a partially fl. luminated background. or be invis- fble." It has been demonstrated therefore, that there is invisible lightning, paradoxical as that may seem.
 Mr Larsen is continuing his ex. perinents for the Smithsonian and | now studying light waves given of by various substances. solid and llauid, many of the specimens fol his study having been loaned to him by the National museum