1830-3 
On the Sandstones of the Quarries near Agra . 
159 
intervals successively : the heaviest (about 20 lbs.) first, and continued until the 
fracture took place ; the lesser weights varied from 5 to JO lbs. 
The first set of experiments was made upon slabs in their dry state ; the second 
after the specimens had been immersed in water until saturated ; excepting, however, 
specimen 12, which was only immersed for two days, and as it gained in weight only 
2flbs., it is probable that, though wet through, it was not completely saturated : its 
superior strength, compared with that of the other specimens, favors this opinion. 
The application of this material in roofing has been very general at and about 
Agra ; and in the old palaces in the fort there are some very curious combina- 
tions ; descriptions of which, with drawings, I shall communicate to you in another 
paper. To those who may wish to use sandstone, either as architraves for doors or 
colonades, or in roofing, the annexed tables, though limited, are sufficiently copious, 
and furnish every information relative to transverse strength. A more complete set 
of experiments on the stiffness and direct cohesive force of the same material are 
in course, and the results shall be forwarded to you as soon as possible ; in the 
mean time, it is to be hoped, that those in whose neighbourhood quarries exist, will 
be induced to follow up the subject, and publish the results of their experiments 
in your valuable periodical. 
At Allahabad and Cliunar there are quarries; and as both these stations are 
conveniently situated for water carriage, it would be particularly desirable to 
ascertain the capabilities of their several productions. 
A paper on the geology of the sandstone districts having been already prepared 
by an able geologist and acute observer, I shall pass over this part of the sub- 
ject, mentioning only that the sandstone in use here is quari’ied at Rupbcb, 
Puharpur, and other villages lying W.S.W. from Agra, and distant about 35 
miles. There are two principal varieties, (geologically three ;) the red, which is 
laminar, and the white or salmon colored, which is compost, and very finely 
granular : the latter is obtained with difficulty in slabs less than 4 inches thick ; 
the former may be had in plates of less than ^ an inch. 
By a reference to the tables it will be seen that the red sandstone does not lose 
much, if any, of its strength by being saturated with water, which renders it par- 
ticularly fit for the purposes of roofing ; and though, in its dry state, it 
is far inferior to the salmon colored variety, (as 11 to 17 nearly,) yet 
when wet, it is something superior to it, (as 11 to 9 nearly,) the latter losing about 
one half of its strength by immersion in water: for the cause we may probably 
look to the different arrangement of the component particles of each variety. In 
the first, they are arranged in parallel and contiguous plates, and derive very little 
strength from the cementing paste in a lateral direction, as is evident from the 
readiness with which they yield to cleavage in this direction ; in the second, they are 
entirely dependant upon this paste for their strength, both in a lateral and other 
directions, the particles being arranged without any apparent regularity, and 
being retained in position merely by the paste which unites them : when this, 
therefore, becomes softened, or partially so, by water, the cohesion is lessened 
or destroyed, and the strength of the material proportionably impaired. A stone 
architrave lately came under my observation, which had failed, in consequence 
of being wetted, though it carried its load well enough when dry. 
Both varieties of this sandstone have been very largely employed in buildings 
at and about Agra, for the last two centuries. The fort of Agra, the tomb of 
the Emperor Akber at Secandra, together with its gateway, the stupendous 
gateway of the shrine of Selim Chisti at Fattehpur Sikri, the jamma musjids 
and palaces of Agra and Dehli, the gateways of the taj at Agra, and the 
tombs of Hamaiun and Sefdar Jang, together with the famous cutub minar 
at Dehli, are almost entirely constructed with the red variety. The palaces 
in the garden at Dig, (among the most beautiful specimens of oriental architec- 
ture extant); the new cacheri at Bhartpur; the two famous temples at 
Mattra, one of which is only just completed ; and the beautiful tombs of Siiraj 
Mai and Balddo Sing, at Gowardban, are examples of the salmon colored sand- 
stone. The roofs of some of these buildings (particularly the Gopdl Bkowan at 
Dig) are very wide, but ai'e, nevertheless, covered in by a seines of single slabs 
spanning from wall to wall. 
To the red sandstone, except for flooring or roofing however, there are objec- 
tions : it decomposes readily by the action of the atmosphere, and is, therefore, 
useless for outside work or ornament, and its deep fciuck dust color is unfavor- 
able to its application in buildings of the modem style of architecture. The 
salmon colored variety has not these objections, and may he classed among 
the most valuable building materials produced in this country : it is very durable, 
