670 THE POPULAR SCIENCE MONTHLY. 



strength. The statement of Prof. Griffin that Milwaukee cement 

 has been shown to have the greatest crushing strength is rather 

 too sweeping, to say the least, as all first-class Portland cements 

 are superior to Milwaukee in this respect, and there are a number 

 of brands of American natural cements that are in every way its 

 equal. Although English Portland cements are among the best 

 in the market, still they are equaled by both German and French 

 Portland, while there are now manufactured in the United States 

 Portland cements that in tensile strength exceed any imported 

 cements. Briquettes made of American Portland have shown a 

 tensile strength of eleven hundred pounds at the end of twenty- 

 six weeks. 



A careful study of the diagrams will give a correct idea of the 

 relative values of typical English and American Portland cements, 

 American natural cements, and Portland and natural cements. 

 It is not intended to show in Fig. 2 that Milwaukee cement is 

 inferior to all American natural cements, but simply that there 

 are American natural cements that under the same treatment will 

 give at least as good results. The numbers along the bottom of 

 the diagrams indicate the age of the briquettes in weeks; the 

 numbers at the side indicate pounds. 



-++*- 



ADAPTATION TO CLIMATE. 



By M. SAINT-YVES MENAED.* 



THE object of the acclimatation of animals and plants is to 

 add to the species, races, and varieties of a country species, 

 races, and varieties of other countries that may be useful or sim- 

 ply agreeable to it, whether they be represented in the wild or the 

 domesticated state. The history of the subject is not compli- 

 cated. It is a general fact that the sciences which we now have to 

 study before entering into the practice of the arts originated after 

 considerable applications of them had been made. They culti- 

 vated wheat long before agronomical institutes were founded; 

 iron was extracted from its ores before metallurgy was known ; 

 we took care of the sick and some pretend that we cured them 

 before the science of medicine existed. So we domesticated wild 

 animals and took them from country to country, from climate to 

 climate, before we had a science of acclimatization to direct us. 

 But while most of the sciences originated in the distant past, the 

 science of acclimatization is new. Something is indeed said on 

 the subject in the books of Buffon, Bernardin de Saint-Pierre, 



* From a Lecture before the Sccidte de Medeeinc Pratique. 



