"On occasion you have made reference to log scale or partial log scale charts as a way to gain better perspective when viewing longer term charts, particularly gold. Do you have any rules as to when to refer to the log scales, and what do they tell you that the normal charts do not?"

David Fuller's view One could write a chapter on this subject but I will resist the temptation. The short answer is that it is a matter of personal choice, and the more you view price charts, the better qualified you will be to select the presentation best suited to your own analysis. In other words, it is important that you feel comfortable with the graphic presentation that you are using, and reasonable men and women can have different views on this subject.

Generally, I prefer semi-log for viewing long-term history, particularly where significant gains have occurred and I wish to review the earlier price history. I can illustrate this with these longer-term monthly charts of the S&P 500 Index on an arithmetic sale chart and also a semi-log graph showing percentage changes.

For shorter-term history - in this instance 5-year - I prefer arithmetic to semi-log, mainly because I do not want to visually exaggerate a slump or condense an advance as this can make it harder to identify potentially significant change.

In another example, while Apple's dramatic upward acceleration earlier this year shows up on both arithmetic and semi-log scales, I find that the equal percentage changes of the latter do not enhance my perception of this unsustainable rate of advance.

These are some of my thoughts on the subject but as I indicated at the beginning, you and every other subscriber should decide what type of graphic presentation works best for you.