STUDIES ON MUSEUMS AND KINDRED INSTITUTIONS. 387 



safer and iioiiseless circiilatioii. The condensed .steam is forced back 

 to the boilers by self-reoulatino- steam pumps. 



The temperature in the main rooms is automatically regulated by 

 Johnson thermostats. This apparatus was invented by Professor 

 Johnson, of Milwaukee, and perfected to its present successful applica- 

 tion. The flohnson Temperature Regulating* Company, Fourth avenue, 

 New York, has already set up such apparatus in hundreds of buildings. 

 The most essential portions of the apparatus consist of diaphragms and 

 cut-ott" valves to control the source of heat, moved by compressed air, 

 and thermostats, which regulate the flow of compressed air to the 

 valves by the movement of a compound ))and. This band is to be 

 adjusted so that the desired range in the temperature may thereby be 

 attained. The ventilating sj^stem is independent of the heating, so 

 that it may be set in motion according to the need of the different 

 times of day. The fresh air is warmed a little so that it does not dis- 

 turb the equilibrium of temperature in the rooms. This warming 

 is also regulated 1)}" thermostats. The S3\stem of ventilation insures a 

 thorough circulation, l)ut at the same time prevents a draft. All the 

 main rooms are sufficiently provided with fresh air, which is changed 

 on an average six times an hour. The exhaust air is drawn off' accord- 

 ing to the need. The cloak rooms, toilet rooms, etc., the kitchen, 

 which is fftted up in a specially ingenious manner, and the laundry 

 have exhausters only. The air is here renewed from ten to fifteen 

 times an hour. 



The fans which supply the air are centrifugal blowers, which are 

 driven by direct-acting, high-pressure engines. These fans, the 

 engines, and the heaters occupy a special room in the cellar. The 

 exhausters on the roof are discoidal ventilators, which are driven by 

 direct-acting electromotors. 



LKillTING OF INTERIORS. 



I saw for the first time in the Boston Art Museum a lighting of 

 rooms l)y windows with prismatically-ribbed panes, which made it 

 possible to illuminate otherwise somewhat dark wall surfaces in such 

 a manner by daylight that they were thereby adapted to the hanging 

 of pictures. When on('(^ my attention Avas attracted to this matter 1 

 fomid such pi'ismatic panes in use in many other places. I hunted up 

 the business office of the American Luxfer Prism Com])any, !•>(> Fifth 

 avenue, New York, a company which originally had its headciuarters 

 in Chicago, but which now has its central office in London under the 

 name General Luxfer Piism Company, with branches in Chicago, 

 Toronto, London, Paris, and Berlin. In the United States the Ameri- 

 can Luxfer Prism Company has its offices in seventeen other cities — 

 an extensive industry whose products are widely distributed. 



It is tlu> more astonishing that nuiseums have not yet directed their 

 attention to this matter, for nowhere did 1 iind this glass in use except 



