PARK AND CEMETERY. 
.3t 
THE HAHNEMANN MEMORIAL, WASHINGTON. D. C.; CHAS. H. NIEHAUS, SC. 
Two well-planted intersecting streets make a handsome setting for this monument in a triangular park plot. 
own individuality and is pediaps differ- 
ent from any other in the kinds of trees 
used or in the manner of treatment. 
The trees have not had all the attention 
in the way of pruning and protection 
they deserve but the management has 
been much better than the' no-manage- 
ment too commonly witnessed. 
Good street-planting and keeping ne- 
cessitates some kind of public or gen- 
eral authority and control. It needs 
considerable knowledge of trees and 
their particular pecularities that proper 
selection may be made. It requires not 
occasional attention, perhaps once a 
year, but all the time to some extent, 
and all that is required when it is re- 
quired, as a skillful husbandman tends a 
growing crop. 
W. R. Smith, superintendent of the 
Botonica! Gardens, who, it is interest- 
ing to note, is the oldest employe of 
the government, having been appointed 
to that position in 1853, recently gave a 
talk on the trees of Washington before 
the Oldest Inhabitants’ Association, tell- 
ing of their superiority to those of any 
other cit}^ He mentioned especially the 
lindens, and, comparing them with the 
famous lindens of Berlin, said that. they 
surpass the latter in size, beauty, and 
number. He says that there are nine 
miles of lindens in Washington and 
only one mile in Berlin. 
Many of the old trees are landmarks ■ 
that should be carefully preserved. 
CONCRETE SURFACE TREATMENT IN CHICAGO PARKS 
Linn White, engineer of the South 
Park Commission, Chicago, gives an 
interesting account of the very success- 
ful work in concrete construction in the 
new public service parks of that sys- 
tem in a recent issue of Cement, un- 
der the title of “The Treatment of Con- 
crete Surfaces," from which we make 
the following extracts : 
The imperfections in the exposed sur- 
faces of concrete are due mainly to a 
few well-known causes which may be 
summed up as follows : 
1. Imperfectly made forms. 
2. Badly mixed concrete. 
3. Carelessly placed concrete. 
4. Efflorescence and discoloration of 
the surface after the forms are re- 
moved. 
Forms w-ith a perfectly smooth and 
even surface are difficult and expensive 
to secure. Made of wood, as they usu- 
ally are, it is not practical to secure 
boards of exact thickness, joints can- 
not be made perfectly close, the omis- 
sion of a nail here and there allows 
warping and the result is an unsightly 
blemish where least wanted. 
Badly mixed concrete gives us irreg- 
ularly colored, pitted and honeycombed 
surfaces, with here a patch of smooth 
mortar and there a patch of broken 
stone exposed without sufficient mortar. 
Careless handling and placing will pro- 
duce the same defects. 
It is of doubtful efficiency to line the 
forms with sheet metal or oilcloth. Im- 
perfections still -appear. 
Two methods suggest themselves as 
likely to overcome the defects alluded 
to above. (1) Treating the surface in 
some manner after the forms are re- 
moved to correct the defects, and (2) 
using for surface finish a mixture which 
will not take the imprint of and which 
will minimize rather than exaggerate 
every imperfection iri the for-ms and 
which will not effloresce. 
Methods of treating the surface by 
bush hammering, tooling and scrubbing 
with wire brushes and water have been 
described in various published articles, 
all of which have for their object the 
removal of the outer skin of mortar in 
which the various imperfections exist. 
But the method most used in the South 
Park work is the acid treatment. It con- 
sists of washing the surface with an acid 
preparation to remove the cement and 
expose the particles of stone and sand, 
then with an alkaline solution to re- 
move all free acid, and finall}'- giving it 
a thorough cleansing with water. The 
operation is simple and always effective. 
It can be done at any time after the 
forms are removed, immediately or 
within a month or more. It requires 
no skilled labor — only judgment as to 
how far the acid or etching process 
should be carried. It has been applied 
with equal success to troweled surfaces, 
like pavements, to molded forms, such 
as steps, balusters, coping, flower vases, 
etc., and to concrete placed in forms in 
the usual way. It, of course, means 
that in the concrete facing only such 
material shall be used as wdll not be 
affected by acid, such as sand or 
crushed granite. It excludes lime- 
stone. 
Treated surface can be made any de- 
sirable color by selection of colored ag- 
gregates or by the addition of mineral 
pigments. The colors obtained by se- 
