FRAGMENTS OF SCIENCE. 



857 



on Saturday will enable us to solve some of 

 the enigmas of solar phenomena and consti- 

 tution." 



Source of the X Rays. Professor Trow- 

 bridge, of Cambridge, and J. E. Burbank 

 have recently published (American Journal 

 of Science, February, 1898) the results of 

 an investigation into the source of the X 

 rays. The experiments were conducted with 

 Crookes tubes containing no interval be- 

 tween the anode and cathode, so that no dis- 

 charge in the usual sense occurred in the 

 tubes. A continuous conductor was led 

 through the rarefied tube, and it was discov- 

 ered that X rays were given off from every 

 element of this conductor at right angles to 

 its surface when a disruptive discharge oc- 

 curred in the circuit of which the tube 

 formed a part. This remarkable result was 

 obtained by means of the very high electro- 

 motive force from a Plante rheostatic ma- 

 chine which was charged by ten thousand 

 storage cells. Among the interesting data 

 obtained were some regarding the so-called 

 Xray burn. When the back of the hand- 

 was exposed to the brush discharge from one 

 of these tubes, a peculiar pricking sensation 

 was experienced and all the symptoms of an 

 X-ray burn developed. The skin when ex- 

 amined under a microscope exhibited centers 

 of inflammation surrounded by regions of 

 lesser degrees of burn. It thus seems evi- 

 dent that the so-called X-ray burn is due to 

 an electrification a discharge at the surface 

 of the skin and this electrification may or 

 may not be accompanied by the X rays. The 

 results of the experiments are summed up as 

 follows : 1. A Crookes tube inclosing a con- 

 tinuous conductor is well suited, with the 

 employment of high electromotive force, for 

 the study of electric lines of induction. 2. 

 The direction of the so-called X rays and 

 cathode rays can be changed by electric in- 

 duction. 3. The so called X-ray burn can 

 be produced by an intense state of electrifi- 

 cation. 4. The so-called cathode rays and 

 X rays are given off from every element of 

 a continuous conductor at a high stage of 

 the vacuum in a Crookes tube, both when 

 this conductor constitutes the cathode and 

 when it forms the anode of the electrical 

 circuit. The term electric rays, possibly 

 rays of polarization, would appear to be 



more comprehensive than the terms cathode 

 rays and X rays. 



Early Observations of the Zodiacal Light. 



Apparently the earliest mention of the 

 zodiacal light is a notice by Diodorus Siculus, 

 of the appearance in the sky, in b. c. 373, 

 " of a great light for several nights, which 

 was called, from its shape, the burning 

 beam." Nicephorus, in his Ecclesiastical 

 History, tells of a remarkable appearance in 

 the sky for a considerable time during the 

 summer and fall of a. d. 410, which he 

 thought could not be a comet, because it had 

 not a stellar nucleus. Cassini saw a simi- 

 lar phenomenon in March, 1668, and his 

 nephew Maraldi another in March, 1702 ; 

 but Cassini's observation was of a comet, the 

 head of which was not visible to him, while 

 it was seen in the East Indies and at the Cape 

 of Good Hope. The first person to give a 

 definite description of the zodiacal light was 

 Joshua Childrey, who is quoted by W. T. 

 Lynn in the Observatory as saying that " in 

 February, and for a little time before, and a 

 little after, that month (as I have observed 

 several years together), when the Twilight 

 hath almost deserted the Horizon, you shall 

 see a plainly discernible ray of the Twilight 

 striking up toward the Pleiades or seven 

 stars, and seeming almost to touch them. It 

 is to be observed any clear night, but is best 

 illuc node. There is no such ray to be ob- 

 served at any other time of the year (that I 

 can perceive), nor any other ray at that time 

 to be perceived darting up elsewhere. And 

 I believe it hath been and will be constantly 

 visible at that time of the year. But what 

 the cause of it in nature should be, I can 

 not yet imagine, but leave it for further 

 inquiry." 



The Importance of Public Baths. Some 

 interesting statistics are given by Walter 

 Channing regarding the municipal public 

 baths of Brookline, Mass. The baths were 

 opened in January, 1897, and at the time 

 Mr. Channing's article was written, about 

 the middle of May, there had used the baths 

 17,089 bathers, or an average of 451 daily. 

 A somewhat curious difference was noted 

 between the number of males and females. 

 The bathers during the last six weeks, for 

 instance, being divided as follows : Men and 



