Show mastic cement we have had many enquin enquiries ies lately respecting the mastic cement for covering covering the fronts of houses and giving them the appearance of brown freestone we have endeavored to find out oat its composition and have at last we believe obtained reliable information respecting it red lead oil sand and limestone dust in some form cover every comp compound tind of it 50 parts by measure of clean dry sand 50 of limestone not burned reduced to grains like sand or marble dust and 10 parts of red lead mixed with as much boiled linseed oil as will make it slightly moist compose a mastic cement the building of brick to receive it should be covered pitr with three coats of boiled oil laid on with a brush and all suffered ered to dry before the mastic is put on it is laid on with a trowel like plaster but it is not so moist it becomes as hard as stone in the course of a few months care must b exercised not to use too much oil although no evil will be the result excepting that the cement will require longer exposure to harden the oil prevents rain and moisture penetrating and this is the reason why this mastic is is not affected with the weather various compositions will answer about as well as the receipt above we will present a few parts by measure measurer ovelear of clear dry sand parts of powdered limestone and 5 of red lead make a hard bard mastic this may be varied with the addition of I 1 10 0 parts of red lead I 1 00 parts parte of sand 50 parts of whiting waiting and 10 of red lead make a moderately hard cement I 1 00 parts of sand 25 parts of the plaster of paris or the same of marble dust 10 parts of red lead and 5 parts of yellow ochre achre make a very beautiful and hard cement at As stated before all of these compositions must be moistened with boiled linseed linse edoil oil the quantity of oi oil Lisso is so very ter y small in proportion to the other materials t that hat the whole mass is is very porous the oil unites the particles together it is the affinitive agent the sand ac must be perfectly dry before they are mixed together that is they must be subjected to heat in an oven to drive off all the water contained in them the sand should not be too coarse and should be passed through a fine sieve various coloring substances may may be employed to mix with the above composition such as any of the pigments used in oil painting we would never use less than 10 parts of red lead in the cement the above compositions might be into statues and works of art by oiling the patterns inside before putting in the coin composition position and allowing the mastio mastic to harden in the moulds before it is is removed two ounces of rosin pounded very fine should be added for eve every ry pint of oil used the whole must be mixed with great care to make the cement properly scientific american VOLCANIC EFFECTS we have been favored with some observations observation 11 made by baron de derloo a belgian naturalist and traveler now residing in our city showing that an important change has taken place in the level of the ground about th the e mission during the last twenty mouths the surface of the earth at the mission has been elevated about 18 inches but the change was not accompanied compa nied by any perceptible quake or subterranean noise it is well known that very remarkable changes of this kind are continually going on in south america in the straits of magellan acenan the earth has bus been raised more than 10 feet the islands of chaloe and madre do de dios have raised 16 feet talcahuano 17 feet vina 12 feet in in 12 years and cohina 5 feet in 2 years the earth has likewise been perceptibly raised within a few years at panama viejo and san B bas 1 alta cala |