420 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[NOVKMBKR 



TAULE (C.) OK CHEMICAL ANALYSES. 



Sandstones. 



Silica 



Car1)onate of Lime 



Carbonate of Magnesia .... 



Iron Alumina 



Water and Loss 



Bitumen 



^jwclfic Gravities 



Of drv Masses 



Of Pa'rtieles 



:\lisorI)ent Powers \vlien sa 

 turatod under tlic exliaust 

 ed Receiver of an Air 

 Pump. 



Disinteffrntion. 



Quantity of Matter disin- 

 tegrated 



Cohesive Powers. 



Craig- 

 leitli. 



98-3 

 11 

 00 

 0-6 

 00 

 00 



Darlev 



Dale' 



(Stan- 



'cUffe). 



90-40 

 0-30 

 00 

 1-30 

 1-94 

 0-0 



Hed- 

 don. 



Kento 



901 

 0'8 

 0-0 

 2-3 

 1-8 

 0-0 



2-232 2-628 2-22!) 

 2-64G 2-993 2-CI3 



0-143 



Grs. 

 0-6 

 111 



Grs. 



0-121 



100 



0-1.56 



Crs. 



101 



56 



93-1 

 2-0 

 0-0 

 4-4 



O-.") 

 0-0 



2-247 

 2-62,') 



0-143 



Grs. 

 7-9 

 70 



(U C <Li 



<^ o ^- 



49-4 



28-5 



16-1 



3-2 



4-8 



0-0 



2-33S 

 2-756 



0-151 



Grs. 

 7-1 



Maqne.iian Limestones. 



Bnls- 

 ovcr. 



3-6 

 511 

 40-2 

 1-8 

 3-3 

 0-0 



2-316 

 2-833 



0-182 



Grs. 

 1-5 



117 



Huddle 

 stone. 



2-53 

 54-19 

 41-3/ 

 0-30 

 1-61 

 00 



2147 

 2-867 



0-239 



Grs. 

 1-9 

 61 



Roach 

 Abbev. 



0-8 

 57-5 

 39-4 

 0-7 

 1-6 

 0-0 



2-134 

 2-840 



0-248 



Grs. 

 0-0 

 55 



Park 

 Nook. 



0-0 

 55-7 

 41-C 

 0-4 

 2-3 

 0-0 



2138 

 2-84 7 



0-249 



Grs. 



1-8 

 61 



Oolites. 



Limestones. 



Ancas- 

 ter. 



0-0 

 93-59 

 2-90 

 0-80 

 2-71 

 \ Trace 



2-182 

 2-687 



0-180 



Grs. 

 7-1 

 33 



Bath 

 Box. 



U-0 

 94-52 

 2-50 

 1-20 

 1-78 

 A Trace 



1-839 

 2-675 



0-312 



Grs. 



10-0 



21 



Port 

 land. 



Ketton 



1-20 

 95-16 

 1-20 

 0-50 

 1-94 

 A Trace 



2-145 

 2-702 



0-206 



Grs. 

 2-7 

 30 



0-0 

 92-17 

 410 

 0-90 

 2-83 

 A Trace 



2-045 

 2-700 



0-244 



Grs. 

 3-3 

 36 



Bar- 

 nack. 



0-0 

 93-4 



3-8 



1-3 



1-5 

 A Trace 



2-090 

 2-627 



0-204 



Grs. 

 16-6 



Chil- 

 mark. 



10-4 

 79-0 



3-7 



2-0 



4-2 

 A Trace 



2-481 

 2-621 



0-053 



Grs. 

 9-8 

 101 



Ham- 

 hill. 



4-7 



79-3 



5-2 



8-3 



2-5 



A Trace 



2-260 

 2-695 



0-147 



Grs. 

 9-5 

 57 



Explanation. — This Table gives the Results of the Chemical Analyses of Sixteen Specimens of Stone, arranged according to their respective Classes. The 

 Names of the Quarries from whence the Stones are obtained are given in the First Line, and the Specimens are considered to be fair average Samples of the 

 ■n-orkable Stone in such Quarries. Some Results of Experiments upon the same Stones, extracted from Table D., are added for the Purpose of att'ording a 

 Comparison of their several Physical Qualities. 



EXPLANATION OF TABLE P. 



The first column exhibits the names of the quarries -whence the several 

 specimens have been procured, such specimens being considered a fair 

 average sample of the stone wliich tliose quarries respectively produce. 



The second column indicates the weights of t)ic specimens in the state in 

 which the stones arc usually employed for building jjin-poses. having been 

 subjected to none but tlie atmosjiberic iufluenccb since they were taken from 

 their respective quarries and worked. 



The third column cnntains the weights of the same specimens after hriviug 

 been perfectly dried by exposure in heated air for several days. Their rela- 

 tive specific gravities are indicated by these numbers, subject to the errors 

 , arising from ibft'crences in the sizes of tlie culies, which, 0}i account of the 

 accuracy of the measurements, varied but little from each other; tlie specific 

 gravities, however, taken by the most certain nietliod, will be found in columns 

 ten and eleven. The average diflference of weight between two specimens of 

 the same stone is in the dry state 56-7 grains; "the greatest difference being 

 208-8 grains, as observable in that from Box ; and the least 0-2 grains, as 

 ill that from Bramham Moor. This difference is to he attributed partly to a 

 small inequality in the sizes of tlic duplicate cubes, and partly to variations 

 of density in pieces of the same material. The greatest difference of weight 

 between two specimens of ditfercnt stones is 1618-3 grains; the heaviest 

 being that of (he Kefton Rag, weighing 5201-8 grains, and the lightest tliat 

 from Totteruboe, weighing 3583-5 giains : the proportion, therefore, of the 

 weight of the lightest to that of the heaviest is as 1 ; 1-452. 



The fom-th column exhibits the weights of one set of the above-mentioned 

 cubes after haxiiig been immersed in water for several days, so as to become 

 completely saturated, such weights having been ascertained immediately after 

 the cubes were taken out of the water ami wiped. 



The fifth column shows the rliffercuee of weight between the same speci- 

 men in its dried and in its saturated state, and indicates therefore the quan- 

 tity (by weight) of water absorbed by each stone. The greatest quantity of 

 water any stone absorlied was 519-8 grains, and the least 57-5 grains; the 

 former from Cadeliy, the latter from Chilmark, (B.) 



The sixth column shows the relative bulk of water absorbed, eight cubic 

 inches, or the bulk of the cube experimented upon, being taken as unity. 

 From these numbers it ajipcars that the specimen from Cadeby absorbs one 

 (|uai-ter of its bulk of water, while the specimen (B.), fi-om Chilmark, does 

 not absorb one thirty-sixth of its bulk ; the fonner absorbs, therefore, about 

 nine times more than the latter. 



The seventh cohinin gives the quantity of disintegration, in grains, of the 

 several stones, after ha\ing been simultaneously subjected to Brard's process 

 for eight successive days. A description of the details of this process here is 

 considered unnecessary, as they are fully described in the thirty-eighth volume 

 of the " .'\nnales de Cliimie et dc Physique;" where is also to lie found an 

 account of tlic experiments made by members of the jnihlie commissions ap- 

 pointed to ascertain its efficacy, from which it appears that tlie measures thus 

 obtained may be considered very closely to rejn-esent the action of the 

 atmosjihere during successive winters on the various stones submitted to ex- 

 amination. 



The eighth and ninth columns contain the results relating to the cohesive 

 strength of the stones, or their resistance to pressure, These experiments 



were made at the manufactory of Messrs. Bramah and Robinson, with a six- 

 inch hydrostatic jiress, the pump of w hich was one inch in diameter. Ac- 

 cording to trials previously made by Messrs. Bramah and Robinson, one 

 pound weight at the end of the pump lever produced a pressure on the face 

 of the culie equal to 2-53 ewt., or to 71-00 lbs. on the square inch. The 

 experiments with the stones were cautiously made ; the weight on the lever 

 was successively increased by a single pound ; and, in order to ensure greater 

 accuracy, a minute was allowed to elapse previous to the application of each 

 additional weight. The eighth column shows the prcssm-e at which the 

 stone commenced to crack, and the ninth column the pressure at which it 

 was crushed. The unit assnmed is the one pound weight placed at the end 

 of the lever. The cm]iloymcnt of this unity in the table is preferred to stat- 

 ing the calculated weights, because it is not wished to give a greater appear- 

 ance of accuracy than can strictly be adjudged to the experiments; but if 

 absolute measures be required, the pressure, either upon the face of the cubes 

 em]doyed or on one square inch of suiface, may lie estimated, as nearly as 

 the means employed enalile it to be ascertained, by multiplying the figures in 

 the table by either of tlie v.ilucs of the unit above stated. The results having 

 been obtained with the same press, and under the same circumstances, it is 

 presumed that no objection can be made to them as comparative experi- 

 menls. 



The tenth coltimn indicates the s]ieeific gravities of the stones, accurately 

 taken by the means usually employed. 



The eleventh column contains the specific gravities of the solid materials 

 of which each stone is composed, on the supposition that the water absorbed 

 when the atmospheric pressure is removed completely replaces the air which 

 before occupied the pores. 



The twelfth column shows the bulk of water absorbed by the stones when 

 satmated under the exhausted receiver of an air pump, their entire bulk being 

 taken as unity. The quantity of water absorbed in this process may be con- 

 sidered to represent the space occupied by the pores or interstices in the 

 substance, unless we sujipose that in some cases the adhesion between air and 

 the solid particles is so great that the entire removal of the atmospheric 

 pressure is not sufficient to counteract the force. It is certain, when this 

 pressure is not removed, long immersion in water will not occasion the dis- 

 placement of all the air contained within the pores. 



OBSERVATIONS. 



The Mansfield red sandstone seems to form a connecting link between the 

 sandstones and the magnesian limestones. The Chihnark limestone is re- 

 markable for having a large quantity of silica in its composition. The Bols- 

 over magnesian limestone is remarkable for its peculiarly beautiful crystalline 

 structure. All the Umestones. (includiug the oolites) except the magnesian, 

 contain small portions of bitumen. 



If the stones be divided into classes, according to their chemical composi- 

 tion, it will be found that in all stones of the same class their exists generally 

 a close relation between their various physical qualities. Thus it will be ob- 

 served that the specimen which has the greatest specific gravity possesses the 

 greatest cohesive strength, absorbs the least quantity of water, and disinte- 

 grates the least by the process which imitates the effects of weather. A com- 

 parison of all the experiments shows tlus to be the general rule, though it is 

 liable to individual exceptions. 



