Make the mortar bed large enough to hold the material for one course; put in unslaked quicklime in proportion to 1 to 20 or 30 of other material; throw into it plenty of water, and don't have that antediluvian idea that you can drown it; put in clean sand and gravel, broken stone, making it thin enough, so that when it is put into boxes the thinner portion will run in, filling all interstices, forming a solid mass. A brick trowel is necessary to work it down alongside the boxing plank. One of the best and easiest things to carry the concrete to the boxes is a railroad wheelbarrow, scooping it in with a scoop shovel. Two courses a week is about as fast as it will be safe to lay up the walls. * * * * * The _Medical Summary_ recommends the external use of buttermilk to ladies who are exposed to tan or freckles. * * * * * WHAT CAUSES PAINT TO BLISTER AND PEEL? HOW TO PREVENT IT. This subject has been treated by many, but out of the numerous ideas that have been brought to bear upon it, the writers have failed to elucidate the question fully, probably owing to the fact that in most parts they were themselves dubious as to the real cause. Last year W.S. gave a lengthy description in the _Building News_, in which he classified blistering and peeling of paint into one of blistering only. He stated in the beginning of his treatise the following: "The subject of blistering of paint has from time to time engrossed the attention of practical men; but so far as we can follow it in the literature pertaining to the building trade, its cause has never been clearly laid down, and hence it is a detail enshrouded in mystery." W.S. dwells mostly, in his following explanations on blistering paints, on steam raised in damp wood. Also an English painter, according to the _Painters' Journal_, lately reiterates the same theory, and gives sundry reasons how water will get into wood through paint, but is oblivious that the channels which lead water into wood are open to let it out again. He lays great stress on boiled oil holding water in suspense to cause blistering, which is merely a conjecture. Water boils at 212 deg. F. and linseed oil at 600 deg. F., consequently no water can possibly remain after boiling, and a drop of water put into boiling oil would cause an explosion too dangerous to be encountered.