I found some interesting (I think) notes on early efforts at stone

preservation:


Thomas Egleston in 1860 reported success in the use of boiled linseed oil,

brush-applied in the summer when the stone was very hot.


Alexis Julien used the same technique followed by a weak solution of

hartshorn (ammonia) in warm water on 2 Manhattan residences and a Brooklyn

church in 1884.  He found that the treatment would last 4 or 5 years until

it became grayish, partially disappeared & required removal.


The gate houses of the Croton (now Central Park) Reservoir underwent a

process of Castile soap followed by alum solution in 1863.  That same year,

J.C. Coombe was granted a patent for masonry preservation involving

treatment with alkaline salts followed by flourosilicic acid.


In the 1880's, Egleston became interested in formulations of paraffin, oil

and sulfur (omitting the sulfur in the case of sandstones) and recommended

(but did not carry out) such a treatment for Trinity Church in the summer of

1884.  Robert Caffal was issued a patent in 1880 for a "formulation for

waterproofing and preserving building materials" composed of paraffin,

creosote and turpentine.  Dr Caffal used a hot wax method of treatment on

The Obelisk (Cleopatra's Needle) in Central Park in 1885 (it had

deteriorated rapidly since it's arrival from Egypt in 1880).


Caffall was living in Phila in 1883 and treated some buildings there and in
New

York with "a mixture of paraffine and carbolic acid."  He reported heating

the stone with a flat-sided stove (curved areas and moldings being heated by

means of a blast flame from India-rubber bags of illuminating gas).


In Sweet's Catalogue of 1906 appears a two step Farnham Patent method sold

by the National Waterproofing and Cleaning Company, using a hot paraffin

application followed by sandblasting to remove excess material.  The

advertisement reported the treatment having been used at the US Post Office

in Minneapolis, the State House in Boston, the New Government Printing

Office in Washington DC, the Studebaker Memorial Church in South Bend

Indiana, and on buildings of the US Naval Academy at Anapolis.


London's Cleopatra's Needle was treated with the Caffall process in 1879,

1895 and 1911, and the same process was used at Trinity Church in 1926.  In

1949, "tarry deposits" were removed from the Needle with an emulsion of

carbon tetrachloride, benzene, and an aqueous detergent; and hot wax was

re-applied.  Central Park's Needle was re-treated in 1913 with China wood

oil.


The article, Chemical Treatments for Masonry: An American History by Norman

Weiss goes on to describe the manufacturing of vinyl resins in the

mid-to-late 1920's, and it's use in the treatment in 1935 of the Tumacacori
National Monument in Arizona.; the 21 colorless products appearing in Sweet's
File in 1942; and the manufactuing of silicone resins in 1943 by the new
corporation,

Dow Corning.


I have 2 pages of the article (don't know how long it was, originally) that

was published (not tool long ago) by the APT.  If any BP'ers are interested,

I could probably figure out how to scan it into an attachment.

Wishing all a good summer


John Mascaro