Experiments on the cohesion of mortar

.Mechanics, Physics, and Chemistry.

70

Experiments on the Cohesion of .Mortar. The following record of experiments on the cohesion of mortar, has been forwarded to us by Mr. B. Baylis, of Chester. was 4~ inches by 4q2 inches. Materials.

The area of the bedjoint

-Proportions. Breaking W e i g h t in lbs.

~ommon lime and sand, Ditto ditto, Ditto ditto, Ditto ditto, ;round lime and sand, Ditto ditto, Ditto ditto, Ditto ditto, Common lime and fine hammer scale, Ditto ditto, Ditto ditto, Ditto ditto, ~round lime and c ~ m e hammer scale, Ditto ditto, Ditto ditto, Ditto ditto, Uommon lime and coarse hammer scale, Ditto ditto, Ditto ditto, Ditto ditto, ~round lime and fine hammer scale, Ditto ditto, " Ditto ditto, Ditto ditto,

2~ to 1 2 " 1 " 1 1 " 1 23 " 1 2 " 1 1

"

1

"

1 1

2½ " 2

"

1

l½ " 1

" " ,' "

1 1 1 1 1 I 1 1 1 1 1 1 1 1

23 2 1

2~

" "

2

"

1

"

1½ "

2½ " 2

"

1

"

1½ "

Broke Do. Do, Do. Do. Do.

at 160 lbs. by accident. at 100 lbs. by accident. at 95 lbs. at 140 lbs. D o . at 235 lbs. Do. at 215 lbs. Do. at 90 lbs. D o . at 100 lbs. Do. at 90 lbs. Do. at 65 lhlg Do. at 270 Ibs. Do. at 280 11~. Do. at 275 lbs. Do. at 260 lbs. Do. at 140 lbs. Do. at 80 lba. Do. by accident. Do. at 130 lbs. Do. at 265 lbs. Do. at 230 lbs. Do. at 265 lbs. Do. at 265 IbM. Lond. Builder, Oct. 1848.

.~lethod of Welding Iron, Steel, and Sheet Iron. In an earthen vessel melt borax, and add to it ~ of s~ ammoniac. When these ingredients are properly fused and mixed, pour them out upon an iron plate, and let them cool. There is thus obtained a glassy matter, to which is to be added an equal quantity of quick lime. The iron or steel which are to be soldered are first heated to redness; then this compound, first reduced to powder, is laid upon them--the composition melts and runs like sealing wax; the pieces are then replaced in the fire, taking care to heat them at a temperature far below that usually employed in welding; they are then withdrawn and hammered, and the surfaces will be found to be thus perfectly united. The author asserts that this process, which may be applied to welding sheet iron tubes, never fails.--Ree, de la Soc. Polytech. Ibid. Sept. tS4S.

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The Copying Telegraph.

Experimental trials have been recently made of t~e copyingelectrie tele- " graph invented by Mr. Bakewell, by means of which it is intended to mako fac simile copies of written communieations, so th at correspondents in distant' towns may reeognize each other's handwriting. The experiments were