26 



NA TURE 



S^Nov. 8, 1 88^ 



is not suitable for a compressible substance. The height 

 from which a bushel is filled affects its amount ; a blow 

 upon its side during filling causes evident settlement, and 

 finally we are not certain as to whether a heaped bushel 

 or a struck bushel is always meant. Such is one class of 

 objections. Another arises from the fact that, contrary 

 to general opinion, Mr. Wilson holds, and we think 

 proves, that weight per bushel is not an indication of 

 quality. Samples may be readily " sweated," rubbed, 

 beaten, or dressed, until the weight per bushel is not a 

 fair indication of quality. Again, corn which has been 

 swollen with exposure to rain does not return to its 

 former bulk but remains permanently enlarged. Lacuna; 

 or hollows filled with air remain, and the bushel is ren- 

 dered lighter, although we cannot hold in such cases that 

 the quality of the flour has been injured. Again, the 

 shape of the grain has its effect in allowing some to pack 

 closer together in the bushel while others lie looser. 

 Lastly, in oats the proportion of kernel to husk varies 

 immensely, and yet this is not indicated at all by weight 

 per bushel. A very strong point is made with reference 

 to moisture. We have generally considered, and with 

 some truth, that the drier a sample of wheat is the 

 heavier will it weigh in the bushel. This it appears is 

 not to be relied upon, and in numerous e.xperiments it 

 was found that after moisture had been artificially driven 

 off the " measure weight " or weight per bushel was less 

 than before ! Thus in one case " the measure weight 

 with no moisture in the grain was nearly 4 lbs. less than 

 at first, with 9'35 per cent, of moisture" ! This is not by 

 any means contrary to what might be expected. As long 

 as wheat contracts in volume as it dries, so long will it 

 increase in specific gravity. When, however, it reaches a 

 stage at which the moisture evaporated is replaced by air 

 occupying the spaces previously occupied with water — 

 then will the weight per bushel suffer. Hence a very 

 strong case is made out against the bushel and the quarter 

 as standards for quantifying corn. 



The question has a retrospective as well as a prospective 

 interest. The bushel weighs differently every year. Thus, 

 according to evidence laid before the Fiers Court in 

 Aberdeenshire, the weight of a bushel of wheat was, in 

 1856, 57-02 lbs. ; in 1857, 60-3 lbs. ; in 1858, 61-32 lbs. ; 

 in i860, 55-95 lbs. ; and in 1S68, 62-29 lbs. A bushel of 

 wheat then between 1856 and 1868 was found to vary 

 in weight by 6-34 lbs., or 50-72 lbs. per quarter of 8 

 bushels. 



If wheat weighs 50-72 lbs. per quarter less one year than 

 another, it will be found that as a standard of value the 

 quarter is misleading. A quarter of 430 lbs. is 10 per cent, 

 in weight less than one of 493 lbs. Now if in a bad year 

 the lighter wheat is quoted at 48J. per quarter, while in a 

 succeeding good year the heavier wheat is quoted at S^J-. , 

 wheat is said to have gone up 4^., whereas according to 

 weight the prices are the same in both years. 



Wheat may be dearer per quarter and yet be really 

 selling at less money per cental. Hence the calculations 

 made by statisticians as to the fluctuations in the wheat 

 market have up to now all been made on a false basis. 

 It would take us to undue length if we were next to show 

 from this little volume whj- the cental is a better means 

 of quantifying wheat than the bushel or quarter. That it 

 is so we have no doubt whatever, and therefore consider 



that the book before us has done much to inaugurate the 

 use of the cental and the abolition of the quarter in our 

 corn markets. John Wright.son 



ZOOLOGY OF THE NORTH ATLANTIC 

 EXPEDITION 



The Norwegian North Atlantic Expedition, 1 876- 1 878. 

 Zoology : Holothurioidea. By D. C. Danielssen and 

 Johan Koren. With Thirteen Plates and One Map. 

 Annelida. By G. Armauer Hansen. With Seven 

 Plates and One Map. (Christiania : Printed by Gron- 

 dahl and Son, 1882.) 



THESE two volumes comprise Nos. VI. and VII. of 

 the results of the Norwegian North Atlantic Expe- 

 dition. The first, which deals with the Holothurians, 

 contains an interesting account of several new genera (5) 

 and species (6). Of the new forms Kolga liyalina is 

 perhaps the most interesting ; it has been placed in the 

 family Elpididse, of the order Elasmopoda, instituted by 

 Dr. Thdel for some of the Holothurians collected during 

 the Challenger Expedition. Kolga is a small Holothurian 

 (the largest specimen dredged measuring 50mm. in length, 

 i5-2omm. in height, and 12- 15mm. in width) with the oral 

 disk facing the ventral, and the anal orifice the dorsal 

 surface, and having a dorsal collar bearing sucker-hke 

 contractile papillas at the anterior extremity. These 

 papilla:, unlike ordinary pedicels, were found to commu- 

 nicate with the perivisceral cavity by means of spaces 

 formed within the collar. 



After referring to lateral and terminal conical suckers, 

 the translucency of the skin, and cutaneous cellular 

 glands, the authors give a careful description of the water 

 vascular system, dwelling especially on the sand canal, 

 which is especially interesting, for instead of hanging 

 free in the perivisceral cavity, as in the ordinary Holo- 

 thurian, it opens directly to the exterior in front of the 

 collar. The larval condition thus persists, the circular 

 vessel retaining its communication with the exterior 

 through a simple membranous tube. In two other Holo- 

 thurians from this Expedition, constituting the new genera 

 of Trochostoma and Irpa, the sand canal has the outer 

 end attached to the skin but not in communication with 

 the exterior, and in each case there is a madreporic plate 

 developed on the canal within the point of attachment. 

 In Elpidia there is a similar arrangement, but the madre- 

 poric plate is rudimentary or wanting, hence the authors 

 think that Elpidia approximates more closely than Tro- 

 chostoma and Irpa to the larval stage so perfectly main- 

 tained by Kolga. With respect to the blood-circulating 

 system, Kolga differs from the general plan in which the 

 dorsal and ventral vessels originate between the stomach 

 and the intestine, for in Kolga they open from a ring 

 encircling the cesophagus, and as this ring has thicker 

 and more muscular walls than the vessels proceeding 

 from it, it is suggested that it may function as a heart. 



Of the five nerve trunks which emanate from the oral 

 nerve ring, the two dorsal furnish an offshoot to each of a 

 pair of large vesicles containing otoliths, and the two 

 lateral ventral cords send branches to numerous succes- 

 sive auditory vesicles. Each vesicle contains from 20 

 to 130 otoliths. Kolga, which is dicscious and in which 

 there is no respiratory tree, may thus be considered to be 



