36 
duction of the cementing silicate of lime and chloride of sodium (com¬ 
mon salt). The former is firmly attached around each grain of the 
stone, making it compact and unalterable by carbonic or even diluted 
mineral acids, and the latter salt is washed away by water. Mr. Procter 
then proceeded, by experiments, to show the change which takes place 
by mixing the two solutions in a glass, and showing the precipitation 
of the insoluble silicate of lime, which soon attached itself firmly to 
the glass. He also showed that dilute sulphuric acid acted violently 
on Caen stone, but had no action on a block of similar stone treated 
by Mr. Ransomers process, specimens of which he had kindly sent 
to the reader of this paper. This process has been applied to the 
Houses of Parliament at Westminster, the Baptist Chapel, Bloomsbury, 
and numerous other private and public buildings, from all of which, so 
far, the reports are of a highly satisfactory nature. The process is more 
than surface hardening, it is one of induration, increasing the density of 
the stone, instead of forming a superficial coating, and would seem to 
fulfil the conditions that the indurating material should enter the pores 
of the stone sufficiently, and that neither the grain nor colour should be 
affected. Another process, the Silicat Zopissa,^^ was introduced by a 
Hungarian gentleman of the name of Szerehuy. It is a secret process, 
and therefore little can be said about it. It seems to be Kuhlmann’s pro¬ 
cess succeeded by a wash of bituminous material, which Mr. Warrington 
believes to consist of zinc paint thinned down with heavy oil of tar, and 
this diffused in a weak solution of silicate of soda by means of size. If 
this be so, it is open to the same objection as the process of the French 
chemist. Dr. Faraday gives a qualified opinion respecting it. He says 
that although it appeared to him that the composition of Mr. Szerehuy 
rendered the stone at the time of his inspection less absorbent of water 
than that of Mr. Ransome, yet the period of time did not enable him to 
come to any satisfactory conclusion as to which of the two would be more 
or less permanently beneficial; in this opinion Sir R. Murchison coincides. 
Dr. Frankland’s examination would go to show that two or three different 
mixtures have been employed upon respective parts of the Houses of 
Parliament, and that the mixture with which the speaker’s court was 
covered in 1858, had been so decomposed as to leave little indication of its 
original composition, and has required a re-application. If on sufficient 
experience, it is even found to preserve the stone, this will be effected 
at the sacrifice of appearance. In one of the small courts of the Palace 
at Westminster, where it has been tried, the colour is of a gloomy and 
unpleasant tint, not uniform, and the surface already suffering, appearing 
to possess no more tenacity or durability than a coating of any other 
