242 



SCIENCE 



[N. S. Vol. XLI. No. 1050 



ing the waste from the various processes of 

 manxifaeture through which cotton passes. 



The fuel value of two pounds of wood is 

 roughly equivalent to that of one pound of 

 coal. This is given as the result of certain 

 calculations now being made in the forest 

 service laboratory, which show also about how 

 many cords of certain kinds of wood are re- 

 quired to obtain an amount of heat equal to 

 that in a ton of coal. Certain kinds of wood, 

 such as hickory, oak, beech, birch, hard 

 maple, ash, elm, locust, longleaf pine and 

 cherry, have fairly high heat values, and only 

 one cord of seasoned wood of these species is 

 required to equal one ton of good coal. It 

 takes a cord and a half of shortleaf pine, hem- 

 lock, red gum, Douglas fir, sycamore and soft 

 maple to equal a ton of coal, and two cords 

 of cedar, redwood, popular, catalpa, Norway 

 pine, cypress, basswood, spruce and white pine. 

 Equal weights of dry, non-resinous woods, 

 however, are said to have practically the same 

 heat value regardless of species, and as a con- 

 sequence it can be stated as a general propo- 

 sition that the heavier the wood the more 

 heat to the cord. Weight for weight, how- 

 ever, there is very little difference between 

 various species; the average heat for all that 

 have been calculated is 4,600 calories, or heat 

 units, per kilogram. A kilogram of resin will 

 develop 9,400 heat units, or about twice the 

 average for wood. As a consequence, resinous 

 woods have a greater heat value per pound 

 than non-resinous woods, and this increased 

 value varies, of course, with the resin content. 

 The available heat value of a cord of wood de- 

 pends on many different factors. It has a re- 

 lation not only to the amount of resin it con- 

 tains but to the amount of moisture present. 

 Furthermore, cords vary as to the amount of 

 solid wood they contain, even when they are 

 of the standard dimension and occupy 128 

 cubic feet of space. A certain proportion of 

 this space is made up of air spaces between 

 the sticks, and this air space may be consider- 

 able in a cord made of twisted, crooked and 

 Icnotty sticks. Out of the 128 cubic feet, a 

 fair average of solid wood is about 80 cubic 

 feet. It is pointed out, however, that heat 



value is not the only test of usefulness in fuel 

 wood and since 95 per cent, of all wood used 

 for fuel is consumed for domestic purposes, 

 largely in farm houses, such factors as rapid- 

 ity of burning and ease of lighting are im- 

 portant. Each section of the country has its 

 favored woods and these are said to be, in gen- 

 eral, the right ones to use. Hickory, of the non- 

 resinous woods, has the highest fuel value per 

 unit volume of wood, and has other advantages. 

 It burns evenly, and, as housewives say, holds 

 the heat. The oaks come next, followed by 

 beech, birch and maple. Pine has a relatively 

 low heat value per unit volume, but has other 

 advantages. It ignites readily and gives out a 

 quick hot flame, but one that soon dies down. 

 This makes it a favorite with rural house- 

 keepers as a summer wood, because it is par- 

 ticularly adapted for hot days in the kitchen. 

 The fuel qualities of chestnut adapt it par- 

 ticularly to work in brass foundries, where it 

 gives just the required amount of heat and it 

 is therefore in favor. Coastwise vessels in 

 Florida pay twice as much for Florida button- 

 wood as for any other, because it burns with 

 an even heat and with a minimum amount of 

 smoke and ash. The principal disadvantage 

 of the resinous pines is their oily black smoke. 



The museum of the California Academy of 

 Sciences has received as a gift the large col- 

 lection of marine, freshwater and land shells 

 assembled by the late Henry Hemphill. The 

 generous donor is Mrs. Charlotte Hosmer, of 

 Oakland, California, the daughter of Mr. 

 Hemphill. The collection contains between 

 60,000 and 70,000 specimens, representing 12,- 

 000 to 15,000 species, and is particularly rich 

 in west coast species. The museum of the 

 academy has also recently acquired the entire 

 Lowe collection of Indian baskets, pottery, 

 stone implements, Navaho and Chilkat blan- 

 kets, and miscellaneous objects of Indian 

 manufacture and use. This collection com- 

 prises more than 1,500 Indian baskets, and 

 several hundred pieces of pottery and mis- 

 cellaneous objects. The collection of baskets, 

 which is said to be one of the most complete 

 and valuable in existence relating to the 



