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cements, and the tests of different modes of slaking the lime, 
mixing the mortars, and preparing the cements and concretes. 
The mortars were tested, after periods ranging from five 
months to four years and five months, for tenacity, by the 
force required to separate two bricks joined together by 
means of them, and for hardness by the weight which they 
would support, applied over a small circular area. The ex- 
periments on concretes or factitious stones are equally com- 
prehensive, being directed to the composition and consistency 
of the cement, whether best used as a stiff mortar or a semi- 
fluid grout ; to the effect of additions of common lime and 
sand or rounded pebbles and gravel, and to ascertaining the 
proportion of each that would be used to the best advantage. 
The results developed by these investigations are of the 
greatest value, and having been applied in the construction 
of the fort, have now had the test of many years’ experience, 
It would be almost impossible to enumerate the various ob- 
Jects of Colonel Totten’s researches while at Newport. There 
is scarce a subject connected with the art or science of the 
engineer, civil or military, which did not engage his. atten- 
tion, and of which he has not left some record. The thick- 
hess of sustaining walls, the thrust of arches, among the 
More important, and the composition of stuecoes, of paints, 
lackers, washes for stone or brick work, among the less so, 
may here be mentioned. ' 
Perhaps no period of his life is so interesting and so 
affectionately remembered by his professional associates. 
eed, a large proportion of the young officers of the corps 
~ Of those days passed a portion of their time under his com- 
Mand, and acquired their first professional experience in the 
performance of duties under his eye and direction. The dis- 
Position to cultivate science, physical and natural, led him to 
original researches, while his influence stimulated and led to 
