EULOGY ON THE LATE GENERAL JOSEPH G. TOTTEN. 151 



These experiments, made by liis assistant, Lieutenant T. S. Brown, of the 

 corps of engineers, were published in the American Journal of Science and 

 Art, and afterwards, having been revised by the author, in the Journal of the 

 Franklin Institute, a note being added, the calculations extended, and practical 

 inferences drawn therefrom. This memoir and additions are found ia vol. vii, 

 new series, Journal of the Franklin Institute, 1831. Lieutenant Brown's account 

 concludes with the following remarks : 



" In Tredgold's Carpentry, and other similar works, may be found the con- 

 stant numbers ^a) and (c) for nearly all the kinds of wood useful in the arts ; 

 but besides that the numbers are in many instances calculated from insufficient 

 experiments, most of the specimens used in the trials were of European growth, 

 and of course the results obtained are inapplicable to American timber, though 

 bearing the same name. It is much to be desired lhq,t numerous and accurate 

 experiments be made in this country by those having the requisite zeal and 

 opportunities ; our architects will then know with certainty the qualities of the 

 different kinds of woods they are using, and instead of working at hazard and 

 in the dark, as they now too ofren do, they will be guided by the sure light of 

 practical science to certain and definite results. If these experiments contrib- 

 ute ever so little to the attainment of so important a result, the object of their 

 publication will be fully accomplished. " 



A subject of such vital importance in the art of construction as the composi- 

 tion of mortars could not fail to invite, or rather compel, the researches of Colo- 

 nel Totten. No species of masonr}^ is subject to such severe deteriorating influ- 

 ences as the walls and arches of fortifications, especially in our climate ; so 

 severe, indeed, that they almost drive the engineer to despair. Next only to 

 the importance of having the building stones or bricks of a suitable character, is 

 that of uniting them by a strong and durable mortar. Few persons whose 

 attention has not been called to the subject conceive its magnitude, the 

 variety of materials it embraces, and the laborious investigations to which it 

 has given rise. Colonel Totten commenced his researches at an early date, 

 and continued them actively during the whole period of his connexion with Fort 

 Adams. 



His work on " Ilydraulic and Common Mortars " was published in 1838 by 

 the Franklin Institute of Philadelphia. It contains, besides original experi- 

 ments and observations on mortars, hydraulic cements and concretes, transla- 

 tions of essays by Treussart, Pitot, and Courtois, the best French writers on 

 the same subject, and constitutes to this day an authority relied on by Amer- 

 ican engineers. Colonel Totten's experiments extend over the period from 1825 

 to 1838 ; they are especially valuable for the variety of limes and cements, and 

 the tests of different modes of slacking the lime, mixing the mortars, and pre- 

 paring the cements and concretes. The mortars were tested, after periods ran- 

 ging 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 hard- 

 ness by the weight which they would support, applied over a small circular 

 area. The experiments on concretes or factitious stones are equally compre- 

 hensive, being directed to the composition and consistency of the cement, Avhether 

 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 de- 

 veloped by these investigations are of the greatest valuii, and having been ap- 

 plied in the construction of the fort, have now had the test of many year's ex- 

 perience. 



It would be almost impossible to enumerate the various objects 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 



