JUNE 6, 1884.] 
present report is practically a series of explan- 
atory sheets accompanying the maps, it being 
intended, after the survey of the entire region 
is completed, to publish two volumes summa- 
rizing the results,—one on descriptive, the 
other on systematic geology. 
Besides the explanations of atlas sheets and 
sections, which will find ample criticism and 
verification at the hands of the multitude who 
will practically use them in the field, the vol- 
ume contains some practical investigations into 
the character and composition of the differ- 
ent coals; the amount of coal already mined, 
and that which probably remains in the basin, 
not yet taken out; together with an elaborate 
description of the methods employed in pre- 
paring the various maps, and in obtaining these 
results. 
In no scientific work is the personal equation 
of the observer so large as in geological inves- 
tigation ; and it would be well if all our geologi- 
cal workers felt as Mr. Ashburner does when 
he says, ‘‘ In the case of a public survey, I 
believe that all the facts which are used in any 
investigation should be clearly stated, so that, 
from a personal examination of the subject by 
an expert, the results can be accepted with 
confidence, or can be rejected with reason.’’ 
In estimating the amount of commercial coal 
under a given area, Mr. Ashburner first de- 
velops each bed upon a horizontal plane, to 
obtain the actual area of the bed, and then 
calculates the average thickness of coal, not 
only from measured sections, but from practi- 
cal results of shipment from different mines ; 
he also wisely distinguishes the regular from 
the overturned dips, as the amount of market- 
able coal obtained from beds in the latter posi- 
tion is very much less than the average. 
In comparing the thus calculated amount of 
coal originally contained in the Panther-Creek 
basin with the amount that has been taken out 
since the commencement of mining, in 1820, he 
finds that only twenty-seven per cent has been 
sent to market as fuel; while thirty-two went 
to the dirt-banks as refuse, and forty-one per 
cent was left in the mines for roof-supports, 
etc. A practical loss of seventy-three per 
cent of all the coal in a given bed seems much 
too large, and suggests wasteful methods of 
mining and preparing. That these have al- 
ready been somewhat improved, is shown by 
the same figures for the years 1881 and 1882, 
when the percentages are respectively forty- 
six, twenty-four, and thirty, or a loss of only 
fifty-four per cent. 
The fact that the analysis of bony coal taken 
from the dump of one of the collieries (p. 181) 
SCIENCE. 
691 
gives a higher percentage of fixed carbon, and 
less ash, than the analyses of coal sent to mar- 
ket from the same colliery, would seem to sug- 
gest one way in which present processes might 
still be improved. 
Mr. Ashburner recognizes the insufficiency 
of present methods of the analysis of coal as 
a means of determining its relative value as a 
fuel, and it is to be hoped that his future in- 
vestigations will result in some practical im- 
provement inthem. Ina paper in this journal 
(No. 58), he has already pointed out to its 
readers that the previously received estimate 
of the percentage of fixed carbon in anthracite 
is too high. ; 
At the close of the chapter containing the 
many vertical sections obtained of the coal se- 
ries, showing the respective coal-beds in each, 
Mr. Ashburner remarks, that no attempt has 
been made to systematize them, and that he 
believes that it would be impossible to do so. 
He then proceeds to point out some of the many 
inconsistencies in the existing nomenclature of 
coal-beds, but fails to note the reason for these 
inconsistencies. ‘They arise from the assump- 
tion that a given coal-bed is continuous over 
the entire area of a basin; whereas the fact 
is, that, while a certain series of rocks may be 
regarded as coal-bearing throughout the basin, 
individual coal-beds are of only limited con- 
tinuous extent; the coal having been formed 
in small, interrupted areas, not in one broad, 
contemporaneous sheet over the whole area. 
The appendix contains a paper by Mr. Ar- 
thur Winslow, on the use of stadia measure- 
ments in surveying. ‘This very simple, and 
by no means new, substitute for chaining, is, 
Mr. Ashburner remarks, not generally used by 
surveyors in the region; but we doubt, from 
what we know of the average surveyor, if Mr. 
Winslow’s use of the calculus in its discussion 
will_add as much to its favor in their eyes as 
the few practical tests which follow. 
MINOR BOOK NOTICES. 
Logarithmisch-trigonometrische tafeln mit ftinf deci- 
malstellen. Bearbeitet von Prof. Dr. Tu. 
ALBRECHT, Sectionschef im koniglischen preus- 
sischen geodiatischen institut. Stereotypausgabe. 
Berlin, 1884. 16+172p. 8°. 
In Science, vol. ii. p. 174, the six-place 
tables of Dr. Albrecht were spoken of with 
the praise which they deserve. They will be 
found superior to any other six-place tables. 
It is harder to make an improvement in five- 
place tables, since we already have many excel- 
lent tables of this kind. But Dr. Albrecht 
