May 29, 1SS5.] 



♦ KNOWLEDGE ♦ 



461 



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NIGHT SKY FOR MAY (Second Map of Pair), 



Showing the heavens as they appear at the following hours : — 



May 21 at 10 o'clock. 

 May 23 at 9i o'clock. 



May 29 at 0^ o'clock. 

 June 2 at 9i o'clock. 



June 5 at o'clock. 

 June 9 at S| o'clock. 



Mere often than otherwise, the solid plug apparatus is 

 looked upon as complete in itself, and is fixed to the soil- 

 pipe without any intermediary trap. The plumber labours 

 under the delusion that the water-seal within the basin is 

 amply protective against the rise of sewer-gases into the 

 house through the clcset ; and so it would be if it were 

 possible to establish a full and perpetual downflow when 

 the handle is raised ; but, as a matter of fact, an up- 

 draught almost always enters on account of defective 

 ventilation of the drains ; and then, too, the handle is 

 liable to get out of order, and remain fastened up, in which 

 case a continuous inflow of foul gases must inevitably 

 follow. 



About the best form of plug closets hitherto introducetf 

 is that known as " Pear.son's Patent Twin-Basin." It is 

 made in a single piece of white earthenware of the best 

 manufacture. It consists of a double basin, the larger of 

 which is situated in front of, and divided by a partition 

 which dips into the water seal, from the smaller. The 

 refuse from the former is effectually flushed outwards and 

 downwards through the outlet which is placed at the 

 bottom of the latter, and in which a carefully-constructed 

 solid plunger Ls made to lift up and down by means of a 

 vertically-disposed pull-up handle. The overflow, should 

 there be any, is controlled by a ball-valve arrangement 

 within the smaller back chamber, and should preferably be 



