STUDIES ON MUSEUMS AND KINDRED INSTITUTIONS. 391 



to the power station and also a certain size of the district is requisite. 

 In St. Joseph, Missouri, a block of Inisiness houses, with a room space 

 of over 300,000 cubic yards, is heated by the exhaust steam from the 

 electric station situated a mile awa}'. 



On the other hand, it has l)een discovered that the special heating 

 apparatus is more advantageous for very large buildings and single 

 groups of buildings, although the expenditure of coal is not thereby 

 diminished. Of such, there are ver}^ many in Ameri(;a. Most large 

 buildings have their own power plants for electric lighting, electric 

 and hydraulic power for elevators, ventilators, etc., and for the manu- 

 facture of ice and the like, in which the working engines afford steam 

 for heating almost without cost. Chimnej^s project but little above 

 the roofs and never give forth such smoke as among us, especially as 

 in Dresden. In America better coal is burned. Relatively few high 

 chimneys are seen in the cities and they do not attract so much atten- 

 tion on account of the height of the buildings. 1 have already men- 

 tioned the distance-heating of Columbia University. The Grand 

 Hotel on Broadway possesses a plant for electric lighting for four 

 blocks of houses," and the exhaust steam from the engines suffices to 



large single prisms (see fig. 29, p. 388), which receive light direct from the sky on 

 their entire basal surface. They then throw this maximum mass at a fixed angle 

 against tlie perpendicular or oblique, stationary or movable windows of the room, 

 whence prism panes, instead of the usual window glass, di8tril)ute the rays. 



In order that the ideas which we have just traced, and which rest upon physical 

 principles, might l)e put into prai-tice with a result api)roaching as near as possible 

 to the theory, one more invention was recpaisite, namely, that of galvanic glazing. 



Whereas formerly, and still almost universally, the panes are fastened to the 

 framework of windows l)y means of putty or strips of lead, galvanic glazing employs 

 electrolytically precipitated, and therefore to a certain extent plastic, copper as a 

 cement. The single panes, with a framework of thin c(ii)i)er strijjs, are tied to plates 

 of fixed size, and thus placed in the copper bath. In about thirty iiours electrolytic 

 copper is precipitated upon tlie copper strips and this binds the i)anes to their 

 frames firmly and immovably, making them absolutely air proof. 



The advantage of this electrolytic glazing is great. In the first place, the strips 

 separating the panes can be made considerably narrower, which is equivalent to a 

 smaller loss of light; and then such windows are more elastic and much more capa- 

 ble of resistance than puttied windows, and show themselves to be fireproof to an 

 eminent degree. 



While windows glazed in the usual manner immediately iMirst and fall out on 

 being heated, these windows have shown their absolute stabiHty during very many 

 trials. If, while heated, they are struck by a stream of water from the hose, they 

 burst, to be sure, but never fail out. Electro-glazing is therefore to be u.sed especially 

 in elevator and light shafts, since the latter, witli their glazing so little capal)le of 

 resistance, are not only incapable of opposing the devouring element in the different 

 stories, but generally open the way to it. 



«In New York among most of the straight long and cross streets a block east of 

 Fifth avenue is in general from 400 to 420 feet long and 200 feet wide, the long 

 streets from 75 to 140 feet wide, and the cross streets (JO feet witle; west of Fifth 

 avenue a l)lock is gent'rally SOO feet long and 200 to 204 feet wide, tiie long streets 

 being 100 feet wideand the cross streets (SO or 100 feet wide. If you ask the ilistam-e 

 of anyone on the street lu' will usually reply that it is so many blocks. 



