4/2 



NATURE 



March 19. 1896 



entirely distinct and important department of the Office. Storm 

 signals are supplied to all ports at which the local authorities 

 will undertake their management. The report shows that the 

 signals were hoisted at i8o stations, but more recently the 

 number has been considerably augmented by their exhibition at 

 exposed lighthouses, for the benefit of passing vessels. Weather 

 forecasts are prepared three times daily, and are also sent to a 

 selected number of agricultural districts during hay-making. 

 A comparison of the results obtained for these forecasts gave a 

 total percentage of 89, which is considered to be very satis- 

 factory. The department dealing with climatology of the 

 British Isles receives observations from 245 stations ; the results 

 are collated and published in various forms, available for present 

 or future discussions. Much attention is also paid to the col- 

 lection of rainfall values, the comparison of various kinds of 

 anemometers, and other researches. 



THE-report of the Committee, appointed in May of last year, 

 to inquire into the causes of the explosion, and the precautions 

 required to ensure the safety, of cylinders of compressed gas, 

 has now appeared. The Committee, in addition to examining 

 manufacturers of the cylinders in which compressed gases and 

 liquefied gases are sold, and some of the engineers who make 

 and compress the gases, visited works where the manufac- 

 ture is carried on, and conducted a series of experiments to 

 determine the causes of the accidents to cylinders, and on the 

 amount of damage such explosions are likely to produce. The 

 information thus obtained has enabled them to draw up a 

 detailed statement of the conditions which are necessary to 

 secure safety in the transport and use of compressed gas 

 cylinders, and as to the regulations which would be desirable to 

 prevent risk. The risks of explosion fall into two classes, viz. : 

 (i) risks due to negligence in the manufacture, annealing, and 

 testing of the cylinders ; (2) risks due to neglect of precautions 

 in filling the cylinders. As the manufacture is carried on very 

 extensively, and is likely to increase, the Committee think that 

 the risks would be reduced if there were some control of the 

 trade of making cylinders by official inspection. They suggest 

 that there should be a general inspection of all factories manu- 

 facturing compressed or liquefied gases. If an inspector were 

 satisfied that the arrangements at any factory were adequate, 

 and that the precautions laid down in this report were being 

 taken, a certificate would be granted authorising such factories 

 to test and mark cylinders. It is suggested that a first thorough 

 inspection, and an occasional inspection subsequently, at in- 

 tervals of about six months, would be sufficient as a ground for 

 granting and renewing certificates. The report is signed by 

 Profs. W. C. Unwin, C. V. Boys, H. B. Dixon, Dr. A. Dupre, 

 and the Rev. F. J. Smith. 



Hitherto most experiments with the Rontgen rays in this 

 country have been made with the object of photographing living 

 human hands and feet, in which only the bones are represented. 

 On the continent, however, the " new photography" has been 

 employed with remarkable success to delineate the arteries in a 

 hand injected with a substance opaque to the Rontgen rays. 

 Some experiments of this kind are described by Dr. Uberto 

 Dutto, of Rome {Att. R. Ace. Lincei). Observing that the opacity 

 of bones to the new rays is probably due -to salts of calcium, 

 of which they so largely consist, a human hand was injected with 

 a paste of plaster of Paris sufficiently thin to penetrate the 

 smaller arteries, and as soon as this had hardened, the hand was 

 photographed in the usual way, the Crookes' tube being fixed at 

 sufficient distance from the plate to produce sharp outlines. It 

 would be interesting to try obtaining stereoscopic views of such 

 specimens ; this could, no doubt, be readily done by projecting 

 the rays obliquely on the specimen and plate, first from one side 

 NO. 1377, VOL. 53] 



and then from the other. Dr. Dutto points out the great value 

 of this method in facilitating the study ot anatomy. 



In one of a series of articles on the use of the Crompton 

 Potentiometer, which he is communicating to The Electrician, 

 Mr. Fisher gives some very mteresting tests which ha«^e been 

 applied to standard Clark cells. The form of cell used is that 

 supplied by Messrs. Muirhead, in which the positive pole con- 

 sists of a spiral of platinum wire amalgamated and filled with 

 mercury. It is very generally believed that if by any chance a 

 Clark cell becomes short-circuited, then the cell is eitler totally 

 ruined or only recovers after a very long time. Mr. fisher has 

 shown that the Clark cell will stand very much roigher usage 

 than one would think, and still recover even in a very short 

 time. In one set of experiments a Muirhead pattern cell had for 

 one minute a potential applied to the terminals o' xSt volt in 

 excess of the electro-motive force of the cell. Asa result, the 

 electro- motive force rose about three parts in 14 000 ; but re- 

 gained its normal value after ten minutes. After slort-circuiting 

 for one minute through 500 ohms the electro-maive force fell 

 from I '4323 volts to i"43i, but recovered its nomal value after 

 thirty minutes. Short-circuiting the cell througi two inches of 

 No. 18 copper wire for thirty seconds caused a dop from 1*4319 

 volts to below I '431 ; but after thirty minutes it had almost re- 

 covered. A cell having been short-circuitec' through a few 

 inches of copper wire (No. 20) for twenty lours, its electro- 

 motive force fell to O'l; volt. The recovery was at first very 

 slow, and continued so till it reached 0-5 vol, the average rate 

 of recovery being 0*03 volt per hour. Afte this the recovery 

 was much more rapid, and in twenty-four hours the cell had 

 almost completely recovered. The effect o'applying a constant 

 potential of 1*4 volts to a cell which hadbeen " dead" short- 

 circuited for twenty hours, was to very mud hasten the recovery, 

 so that after two and a half hours it hal regained its former 

 value. The author has found that the reistance of a Clark cell 

 rises very rapidly if the cell is used t- send any appreciable 

 current, and he supposes that whatevejis the cause of this in- 

 crease of resistance and the fall of potentil, it in is a great measure 

 of the character of a "skin effect." Some tests made of two 

 cells set up by Prof. Fleming in 1886 r 1887, seem to show that 

 when these cells were in continuou.'use, so that they were em- 

 ployed to send small currents, and had small currents driven 

 through them, their electro-motivf forces were in very much 

 better agreement than when staning idle. From these and 

 other experiments the author crvcludes that the passage of 

 these small currents through sta<3ard Clark cells is decidedly 

 beneficial. 



The South Slavs have a nuiber of independent folk-songs 

 which, unlike the great Homric epics, have not been welded 

 into an harmonious whole. F. Krauss {Internationales Archiv 

 fiir Ethnogi-aphie, vol. ix. ) elucidates these songs by notes on 

 various customs and beliefs especially those relating to death 

 and burial. The South SIvs save money during the whole of 

 life in order to ensure a grfid funeral, and they honour graves 

 and graveyards in many w/s, considering it a crime to cultivate 

 the ground of a graveyard but the Catholic priests of Pozega did 

 not hesitate to do so, and few in them the best cabbages and the 

 largest turnips in the dtrict. There is an amusing account of 

 cuckoo folk-lore in the same journal ; and though .the legends 

 vary slightly, the cuckc is regarded by all the South Slavs as a 

 woman changed into fbird for excessive mourning over a dead 

 son or brother. 



We have receivecfrom Miss E. A. Ormerod the nineteenth 

 of her valuable " Pports on Injurious Insects," dealing with 

 insect pests which ere specially noticeable during 1895. I' i^ 

 fully equal, both ipize and importance, to its predecessors, and is 



