March 15, 1889.] 



SCIENCE. 



197 



mersed in this solution, or the latter may be applied to its surface 

 with a brush. The surface is then rubbed to a face with fine grit, 

 and allowed to dry, after which it is subjected to a diffused dry 

 heat of from 130° to 160° F. in an oven. When the stone to be 

 treated is fixed in position, as in a building, it is stated that the 

 compound may be applied with a brush, either with or without heat 

 subsequently. Although it is admitted that by heating the stone 

 its durability is greatly increased, the London Builder thinks it 

 questionable whether this is practicable on a large scale after it is 

 built up. But even supposing it were practicable, it is very doubt- 

 ful whether the hardened surface would protect the stone for any 

 great length of time. Experience has shown, that, where only a 

 hardened coating has been formed, moisture soaks in, either 

 through the cracks in the masonry or through portions of the sur- 

 face of the stone itself, rendered vulnerable by the defective appli- 

 •cation of the preparation, whatever it may consist of. The moist- 

 ure collects behind the hard coating, and produces a line of weak- 

 ness, in consequence of which the thin crust flakes off. Moreover, 

 it is wrong to suppose, that, because a lime solution hardens a 

 stone, the latter thoroughly resists decay, as has often been sug- 

 gested. The mere fact of the stone being hardened does not add 

 much to its durability from a chemical point of view, unless the 

 hardening material be acid-resisting. The only effect of the har- 

 dening is to render the stone less absorbent, and therefore slightly 

 more durable, for a few years at most. 



— Lord Wolseley, who is not often caught tripping in making 

 hasty statements, writes as follows in the current number of the 

 Fortnightly Review : " The battles of the future will be very dif- 

 ferent from even those of 1870. . . . One remarkable change will 

 be the absence of nearly all that terrific noise which the discharge 

 of five or six hundred field-guns, and the roar of musketry, caused 

 in all great battles. . . . The sound of cannon will be slight, and 

 will no longer indicate to distant troops where their comrades are 

 engaged, or the point to which they should consequently march. 

 Our sentries and advanced posts can no longer alarm the main 

 body upon the approach of the enemy by the discharge of their 

 rifles. The camp or bivouac will no longer be disturbed at night 

 by the spluttering fire of picquets in contact with the enemy. Dif- 

 ferent arrangements for giving the alarm upon the approach of 

 hostile columns will have to be resorted to. The main column on 

 the march cannot in future be warned, by the shots of flanking 

 parties, of the enemy's proximity, and a battle might possibly be 

 raging within a few miles of it without that fact becoming at once 

 apparent." Nature asks that some competent member of the 

 '■ Scientific Corps " will kindly explain. 



— The prefect of police in Paris has issued a new set of regula- 

 tions with regard to the fire brigade service in theatres, which will, 

 it is thought, reduce very much the risk of fire ; so far, at least, as 

 it can be reduced in the many theatres in Paris which have always 

 been, and must remain, from the position they occupy, regular 

 death-traps. A certain number of firemen are allotted to each 

 theatre, who, under no pretence, are to be called out of the theatre, 

 or to receive visits from friends or acquaintances. The chief of 

 the detachment has the responsibility of seeing that all the appara- 

 tus for extinguishing a fire is in its allotted place and in proper 

 order, and the commissary of police is to satisfy himself that this 

 has been done before the theatre opens. During the representa- 

 tion the chief of the detachment must be constantly moving about 

 to see that the men are at their posts, that no one is smoking in the 

 corridors or carrying open lights, and that access to the reservoirs 

 and fire-plugs is not hampered by placing any scenery or stage 

 properties in the way. He is to examine the manometer, and, if he 

 finds that there is a deficiency of pressure in the water-mains, he 

 must inform the nearest post of the fact. In the event of an insig- 

 nificant outbreak, recourse is to be had only to the apparatus with- 

 in reach of the foyer ; but, if the outbreak is of a more serious 

 character, the nearest post is to be informed by telegraph. At the 

 ■close of each representation the firemen are to make a round of the 

 theatre, and see that the iron curtain is lowered, the buckets filled, 

 and the folding doors closed, and, in the event of these not working 

 smoothly, they must be repaired at once. The manager of the 

 ■theatre is required implicitly to obey the orders of the district com- 



missary of police, who, in the event of an outbreak of fire, assumes 

 the sole command of the theatre until the arrival of the prefect of 

 police or the chief officer of the fire brigade. 



— Nature makes the following extract from a letter addressed 

 by Mr. A. W. Tuer to a contemporary : " The melodious hum 

 of skating was perhaps never heard to greater advantage than 

 through the crisp air of a bitterly cold morning little more than 

 a fortnight ago, — the first Sunday in the year. Almost as soon 

 as I-Censington Gardens were entered, one became conscious of 

 a clearly defined musical sound coming from the direction of the 

 Round Pond, — G as nearly as I could judge, but corrected to 

 G sharp, when, half an hour later, I got to a piano. I had wished 

 to compare the notes— probably lower — given forth by other and 

 larger sheets of ice, but procrastination strangled an opportunity 

 which perhaps others will take when it again offers. Comparing 

 a sheet of ice to a taut string, and the countless skates to the hairs 

 of a bow, — scientifically, a poor comparison enough, — the sound 

 might be expected to have been like that produced by the scraping 

 of a fiddle, but it exactly resembled the whistle of a distant loco- 

 motive." 



— The following description of some of the most impoKant fea- 

 tures of the subsurface torpedo-boat lately submitted to the Navy De- 

 partment by the Columbian Iron Works of Baltimore, and the uses 

 for which it is intended, serve to clear up several points which 

 might possibly have caused a misunderstanding as to the nature of 

 the craft. The boat is cigar-shaped, and is capable of being 

 operated under three different conditions : first, above the surface, 

 that is, with nearly half of it above water ; second, awash, that is, 

 with only a few inches of the back exposed, together with the 

 conning tower ; third, completely submerged, that is, with nothing 

 whatever appearing above the surface. In the last condition, 

 which is the primary condition for torpedo warfare, the boat's 

 means of offence is a horizontal tube directly in its axis, from 

 which are discharged 8-inch projectiles either by pneumatic power 

 or by powder. These projectiles are capable of giving several 

 hundred feet range, and the gun and projectile are constructed on 

 a principle first propounded by Lieut.-Commander Barber at the 

 United States torpedo-station in 1S73, but separately invented, and 

 proved successful by Mr. Holland, the inventor of this boat. In 

 lieu of this submarine gun. the boat will be fitted with any kind of 

 locomotive torpedo that the Navy Department may desire to be 

 fired from this or a similar tube. In addition to this tube in the 

 axis of the boat, there is another 8-inch tube, fitted at an angle, for 

 over-water fire at distances of 1,000 yards or thereabout. It is in- 

 tended to use this tube for throwing dynamite shells, under circum- 

 stances where the boat cannot approach the enemy within torpedo 

 range, or where it may be preferable not to try to do so. The boat 

 has a double skin on the upper forward part, separated by about a 

 foot of space ; and this space is filled with water, which flows 

 freely into it. Abaft of this, and forward of the gun-room, is a 

 vertical bulkhead of several inches of iron. When, therefore, she 

 is lying awash, and using her upper pneumatic gun (which makes 

 no smoke), she will be almost invisible to the enemy, and, if struck 

 by machine-gun projectiles, she is almost certain to be uninjured. 



— The wine-making industry in California is the subject of an 

 interesting article by Edwards Roberts in the supplement to Har- 

 per's Weekly of March 9. The article is copiously illustrated. 



— The Eiffel Tower has already attained a height of 280 metres, 

 and in a month it will be completed by the turret and the electric 

 lantern, which will give it its greatest height of 300 metres. The 

 Paris correspondent of the London Builder says, " It is curious to 

 notice to-day how inferior is the effect produced by this enormous 

 piece of iron-work to the idea that people had of it in advance. 

 Seen from the environs of Paris, it overpowers the city, and ap- 

 pears immense by the side of the large monuments, which are re- 

 duced to very small dimensions ; but the nearer one approaches it, 

 the less is one aware of its colossal proportions, and the eye hardly 

 sees what relation can exist between the thin termination of the 

 tower and the gigantic arches of its base. There is an optical 

 illusion about it which will always weaken its general effect, and 

 disappoint the hopes of the promoters of this useless attempt to 

 astonish the eye by its giddy height." 



