2l8 



SCIENCE. 



[Vol. XXI. No. 533 



It is a singular fact that, despite all the improvements of the 

 dioptric system and the vital urgency of the matter, th«side and 

 mast lights of vessels still remain to a large extent in so imper- 

 fect a condition. In Paris and Birmingham, the only seats of the 

 manufacture of dioptric lights, ship lights veith true lenses have 

 long been constructed on the same principles of the sea-lights 

 which have a radius thirteen times as great. The writer has 

 long urged, both publicly and privately, the employment of more 

 powerful lights at sea, and more particularly the equalization of 

 the power of these lights by using electricity in incandescent 

 lamps of unequal intensity, in the colored side lights, so that 

 meeting or passing vessels shall understand the course and char- 

 acter of each other at much greater distances than are now sanc- 

 tioned by statutory rules. At the International Marine Confer- 

 ence in Washington, in 1889, the subject of ship lights was amply 

 discussed with reference to azimuthal ranges and vertical diver- 

 gences, and the conclusions formulated are being now interna- 

 tionally adopted. But the question of greater intensity of beam 

 and of equality of beam does not appear to have been considered 

 in relation to the greatly changed conditions of vessels thronging 

 the high and narrow seas in these days, and to the ever-increasing 

 frequency of accidents by collision at night. I earnestly hope 

 that the authorities of the United States will yet again take the 

 initiative in effecting this final improvement in ship lights. 



In closing for the present these few remarks on lighthouses it 

 is impossible not to give expression to feelings of admiration for 

 the liberal and enlightened policy of the United States in main- 

 taining the lighthouses of their immense coast-line free of toll to 

 all the maritime world. America sets a shining example to 

 many an older country in this as in many other ways May her 

 maritime prosperity abundantly increase ! 



A JAPANESE SICK WITH SCARLET- FEVER.' 



BY ALBERT S. ASHMEAD, M.D., NEW TORK CITY. 



I HAVE been introduced to a .Japanese gentleman, aged 23, liv- 

 ing in Brooklyn, who is undergoing treatment by Dr. Benjamin 

 Ayres for scarlet-fever. As this is the first case of scarlet-fever 

 I have ever seen in a Japanese, I report it to you. To-day is the 

 twenty eighth day of the disease. There has been no temperature 

 during the last two weeks. Desquamation has been general for 

 three weeks, mostly behind the knees and about the shoulders. 

 He has now scaly desquamation on the palms and soles ; noticed 

 first by the patient on the backs of the hands. The throat showed 

 very marked symptoms and is even now very distinctly red and 

 inflamed. Highest temperature 103^; no albumenaria. 



I content myself with this short sketch, as, I think, Dr. Ayres 

 will make a more complete report. 



I am the more interested in this case, as it is supposed that the 

 Japanese have an immunity from scarlet-fever. I have tried, 

 without success, several times to inoculate a Japanese subject 

 with the disease, in the hope of producing a protective virus. 

 More recently I inoculated two children who had been exposed to 

 the contagion of scarlet-fever with the blood-serum from a blister 

 on the body of a child who, having had scarlet-fever previously, 

 was artificially immune. 



These children, whether protected or not, did not take the dis- 

 ease. More recently still, I have inoculated two cases of scarlet- 

 fever with pure blood-serum from a blister on the body of an 

 adult, who was also artificially immune. The inoculations were 

 made in the arms on the third, fourth, and fifth days. In these 

 latter cases there was no effect if diminished desquamation is not 

 to be considered as one. Both cases ran a mild course. It is my 

 opinion, on which, having so little to go upon, I would not insist 

 too strongly, that blood-serum from an artificially immune sub- 

 ject has a virtue, if not curative, at least preventive. Dr. Seward 

 of the Willard Parker Hospital promised me to make a further 

 investigation in the scarlet-fever ward of his hospital. 



I have given you these facts to show you what reasons I have 

 to be particularly interested in the case on which I have sum- 

 marily reported. 



' Communicated to the Tei-I.-Kwai. 



ELECTRICAL NOTES. 



If a student of molecular physics had been asked a few months 

 ago for an explanation of the phenomenon seen when an elec- 

 trical discharge is passed through a Geissler tube, he would not 

 have hesitated in his reply. He would have shown, from the re- 

 searches of J. J. Thomson and others, that the phenomenon, in 

 the case of the non-striated discharge, is akin to that of electro- 

 lysis, that disassociation was a necessary accompaniment ; that, 

 in the ca^e of the striated discharge, the electricity was carried 

 partly by convection and partly by electrolysis, that this was 

 shown by the fact that the conduction did not proceed with the 

 velocity of light, that each stria was a place where electrolysis 

 was taking place, and each dark band a place where the elec- 

 tricity was carried by convection, that the reason why the dis- 

 charge was not produced with mercury vapor is that it cannot be 

 disassociated, and that the reason that it takes place so readily 

 with other gases is that the converse is the case. 



But the recent work of Herr Hertz and Dr. Lenard has caused 

 considerable doubt to be thrown on some parts of this theory. Not 

 that the theory as given above may not be true after all, but it 

 must first explain the phenomena discovered by the above-named 

 scientists, and at present this seems difiScult. 



A short account of them is as follows : If we take a Crookes 

 tube, i e., a tube in which exhaustion has been carried to such an 

 extent that the discharge is no longer visible, except where it 

 strikes upon the glass, or some other solid or phosphorescent 

 substance, we find that, as the exhaustion progresses, the rays 

 issuing from the cathode, and producing incandesceoce or phos- 

 phorescence, instead of passing directly from the cathode to the 

 anode, tend to move in a straight line, normal to the cathode. 

 This discharge has been supposed, one might almost say proved, 

 by Crookes, in a series of most masterly experiments, to consist 

 of highly charged atoms of gas, repelled with great violence from 

 the cathode. As the exhaustion becomes more and more thor- 

 ough, fewer and fewer atoms are left in the tube, and conse- 

 quently the trajectories of the atoms become more and more 

 nearly straight lines, and, if the tube is bent at an angle between 

 the electrodes, the discharge will strike against the glass. 



If this is the real nature of the discharge, it would seem on 

 first sight that it should not be able to pass through a metallic 

 substance. Yet it has been discovered by Herr Hertz that this is 

 not the case, that it passes readily through thin metal plates. 

 From these two facts, that the discharge takes place in straight 

 lines, and that it passes through thin metal plates. Dr. Lenard 

 conceived the idea that it should be possible to produce the dis- 

 charge in a Crookes tube and make it pass out into the air, and 

 the experiment, when tried, proved successful. 



The apparatus used was as follows: A Crookes tube, whose two 

 ends we will call A and B, had the cathode electrode sealed in at 

 A. This was of the usual form, and projected some distance into 

 the tube. The anode consisted of a tube of aluminium, only a 

 little smaller than the size of the glass tube containing it, and 

 surrounding the cathode. On the discharge taking place it 

 would, instead of passing directly from the cathode to the anode, 

 as in the case where the gas was not so much rarefied, proceed 

 normally from the cathode and out of the open end of the alu- 

 minium tube constituting the anode and strike against the glass 

 at the other end of the Crookes tube. In these experiments, that 

 end was cut off, and a metal plate cemented across the opening. 

 In the middle of this metal plate a small hole, 1.7 millimetres, 

 was drilled, and this was covered by a sheet of aluminium, .0003 

 millimetres thick. Consequently, when the discharge struck 

 against the aluminium plate, the latter being permeable to it, it 

 passed out into the air. This was shown by a luminous discharge 

 just outside the sheet of aluminium, and by the fact that phos- 

 phorescent substances placed there behaved in the same manner 

 as when exposed to the cathode discharge in a Crookes tube. If, 

 in place of air, other gases were made to surround the aluminium 

 plate, very different effects were obtained. If the gas was hydro- 

 gen, the discharge, after passing through the aluminium window, 

 was not scattered so much. If carbonic acid gas, the scattering 

 was much greater. Dr. Lenard points out that, as all gases at 



