Keffel’s Germinating Apparatus.—­With engraving. 7074

      Millet.—­Its Cultivation. 7074

VIII.  Miscellaneous.—­Puerta del Sol, Madrid, Spain.—­With
      engraving. 7063

      Dust-free Spaces.—­A lecture delivered by Dr. Oliver J.
      Lodge before the Royal Dublin Society. 7067

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PUERTA DEL SOL, MADRID.

Puerta del Sol, or Gate of the Sun, Madrid, is the most famous and favorite public square in the Spanish city of Madrid.  It was the eastern portal of the old city.  From this square radiate several of the finest streets, such as Alcala, one of the handsomest thoroughfares in the world, Mayor, Martera, Carretas, Geronimo.  In our engraving the post office is seen on the right.  Large and splendid buildings adorn the other sides, which embrace hotels, cafes, reading rooms, elegant stores, etc.  From this square the street railway lines traverse the city in all directions.  The population of the city is about 400,000.  It contains many magnificent buildings.  Our engraving is from Illustrirte Zeitung.

[Illustration:  The Puerta del Sol, Madrid, Spain (From a Photograph.)]

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CONCRETE BUILDINGS FOR FARMS.

Buildings made of concrete have never received the attention in this country that they deserve.  They have the merit of being durable and fire-proof, and of not being liable to be blown down by violent winds.  It is very easy to erect them in places where sand and gravel are near at hand and lime is comparatively cheap.  Experiments made in England show that coal screenings may be employed to good advantage in the place of sand and gravel.  Mr. Samuel Preston, of Mount Carroll, Ill., has a dwelling and several other buildings made of concrete and erected by himself.  They were put up in 1851, and are in excellent condition.  In The Farmers’ Review he gives the following directions for building concrete walls: 

First, secure a good stone foundation, the bottom below frost, the top about one foot above ground.  Near the top of the foundation bed in 2x4 scantling edgewise transversely with the walls, at such distances apart as the length of the planks that form the boxes to hold the concrete may require, the ends of the scantling to run six inches beyond the outside and inside of the wall.  Now take 2x6 studding, one foot longer than the height of the concrete walls are to be, bolt in an upright position in pairs to each end of the 2x4 scantling, and, if a foot wall is to be built, sixteen inches apart, as the box plank will take up four inches.  To hold the studding together