94 ANNUAL OF SCIENTIFIC DISCOVERY. 



has four characters, showing sunrise, meridian, sunset and midnight. The 

 next circle exhibits the odd and even hours ; the even hours are designated 

 by a bold figure, and the odd hours by smaller ones. The dial there has 

 the common minute marks, and on the extreme outside was the Chinese 

 numerals, running from one to twelve. 



FRAME FOR GRAPE VINES. 



Mr. S. O. Cross, of Sandy Hill, N. Y., has invented a very convenient 

 frame or trellis for grape vines. The advantage of the frame is, that it is on 

 hinges at the bottom, so that it can be raised and lowered, pitched at any 

 angle, and either laid upon the ground or made perpendicular. By this 

 means the posture of the vine can be changed according to the weather 

 and the season, without in any way .injuring its vigor and fruitfulness. 



MATERIALS IN THE GREAT WALL OF CHINA. 



In a lecture on China, Dr. Bo wring said it had been calculated that if 

 all the bricks, stones and masonry of Great Britain were gathered together, 

 they would not furnish materials enough for a work such as the Wall of 

 China ; and that all the buildings in London put together would not have 

 made the towers and turrets which adorn it. Builder. 



IMPROVEMENTS IN SAFETY LAMPS. 



After the invention of the wire- gauze safety lamp of Davy, certain 

 imperfections began gradually to reveal themselves. In the first place, it 

 was found to give so little light that the pit-men seized every opportunity 

 of removing the gaiize, finding, in point of fact, that their work could not 

 be done with the imperfect light. And, in the second place, the great fact 

 began to be developed, that this lamp, however secure in a still atmos- 

 phere, was not safe in a current. An account of the various attempts 

 made to remedy the defects of the Davy viz., insecurity in a current and 

 deficiency of light would fill a volume. Until within a recent period, 

 however, two lamps only had been devised, which were able to supersede 

 the Davy, viz., of Clanny and Museler. Dr. Clanny found that if the 

 lower part of a lamp were made of thick glass, and the wire-gauze 

 cylinder retained above this, two things arose 1st. The current of air 

 descended to feed the flame in converging curves, and the gaseous products 

 of combustion ascended in diverging curves. And, 2d, owing to the 

 use of the giass, the gauze, being no longer required to give light, could 

 be made much finer, and even doubled and trebled. The Museler lamp 

 differs from the Clanny only in having a chimney in its interior just above 

 the flame. There were two objections to the Clanny lamps viz., the 

 liability of the glass to fracture on being heated, from a drop of water 

 tailing upon it in this state, and also its liability to fracture from mehcani- 



